(Pocket-lint) - The explosion of smartwatches and fitness trackers has thrown up some real gems and thrown down some real turds, leaving us all to step carefully when choosing a new device. Polar is an established name in fitness devices, one of the oldest, perhaps, when dealing with heart rate monitoring.

A widening portfolio from Polar has seen the birth of more lifestyle devices in the A family and stepping up in functions across the M (sport) and V (pro) devices, with a gradual increase in wider connectivity across the brand's offerings.

The M600 is a rethinking, adopting a proper smartwatch platform and offering those fitness tracker functions the company is known for combined with a lot more on the watch side than you'd normally get. The result is one of the most considered sports devices we've seen and certainly one of the best Android Wear devices to date.

The Polar M600 mates the body module with a rubber strap and, like the TomTom Spark, the body slots into the strap meaning the two sections can be easily separated when you want to clean them.

The design looks a lot like previous Polar watches, although it's pretty thick, meaning you need enough wrist for it to sit on. If you're of the thin forearm variety you might think it's too big, but we found it sat well on an average male arm. The chunkiness gives it some substance and it looks good, both from a sports point of view and as a smartwatch.

Compared to other Android Wear devices, Polar's watch-making experience is apparent, as this is much nicer than something like the Moto 360 Sport and looks better and wears better than that previous attempt. As with other Polar devices the screen is square fitting Polar's family design.

On to the more serious stuff. There's proper waterproofing with an IPX8 rating so it supports swimming, the screen is protected with Gorilla Glass to avoid scratches and the metal detailing that frames the display left and right gives a premium look. There's the choice of black or white, although we'd like to see a choice of strap colours to give the design wider appeal.

The rubber strap is easy to adjust and uses a conventional two pronged buckle, with two bands to stop the spare strap catching on things. Most importantly, the M600 is comfortable to wear and sweat through, and weighing 65g, it's not too heavy either.

Designed as a sports watch first, there are two buttons. The first button to the left side is the standard Android Wear button, letting you go home, wake the display or long press to access the menu.

The second button on the front takes you straight to the sports side, opening the Polar app. This is very much sports territory and we really like that Polar hasn't been distracted by Android Wear: it's taken the platform and owned it, rather than skipping around Google's fancy smartwatch features.

The hardware tells a similar story. With an optical heart rate sensor onboard and its own GPS you're ready to run out the door and leave your smartphone at home. There is no compass or barometer, however, so direction and elevation is based on GPS. There's also support for accessories, so if you have an H7 Polar chest strap, you'll get the option of using that, which might be the preferred option for cyclists.

One of the skills that Polar does adopt from Android Wear is the support for Bluetooth headphones and local storage for your music, meaning you can take your music with you on the run, again without your phone. TomTom Spark 3 offers this, as does Apple Watch 2, and it's a feature that is sure to be popular.

The great thing is that this full feature set, supported by this hardware, makes for a great fitness device, before you even touch the smartwatch side of things.

The Polar M600 is powered by a MediaTek chipset with 512MB RAM and a standard 4GB of storage. The battery is 500mAh which is pretty good for this type of device and explains the thickness.

There's a 1.3-inch display on the front with a 240 x 240 pixel resolution. This isn't the largest or sharpest Android Wear watch display, but as we said, the screen fits and we found it a good size for reading on the move. It supports always on functions, dimming in normal wear and brightening up when you move the watch to look at.

As an LCD this is a backlit full colour display so it's illuminated, rather than using the lower power displays that some other sports watches offer. It looks great, which adds to the appeal, but does draw more heavily on the battery than the mono TomTom or Garmin displays, for example. It does have an ambient light sensor, however, so adjusts to the lighting conditions around you.

The 500mAh battery will give you about 2 days of use when connected to an Android device, including exercise time. You might be able to push it to a little more in casual wear. We've not tested the Polar M600 with an iPhone, but reports suggest this drops to about a day with Apple's phone. In reality, the Android Wear experience is much enhanced when paired with an Android phone and at least you have the option, unlike the Apple Watch.

Two days is good for Android Wear devices, but it does mean regular charging compared to many other sports watches which will often give you perhaps 5 active days or more - but without really offering any smart functions.

That's the trade-off here: the Polar M600 doesn't have great endurance in sporting terms, but it offers a whole lot more in terms of functionality, meaning it does a lot more than just tell you the time when you're walking around.

Charging is via the magnetic connection point on the rear and over the past weeks that we've been using the M600, we've typically opted to charge every other day without it running flat. The charger neatly attaches to the rear of the watch without needing to clip anything on or fiddle around.

To get the M600 up and running you need two things: the Android Wear app and the Polar Flow app on your phone. The first handles the connection to your phone, the second syncs with your Polar account and syncs the data from your watch.

Using Android Wear on an Android smartphone makes for a fast and easy connection as the devices are designed for seamless cooperation. Once you're connected, you can use the Android Wear app to control many of the smartwatch functions, like deciding what notifications you want from your M600 and so on.

The Android Wear app will also then sync your apps, so anything you have on your device that's compatible with Wear will then move over - like Spotify, Play Music, Citymapper and even other fitness apps if you want to use them.

The Polar Flow app then handles everything else. This is where you'll view your stats and be able to get a good look at your activities you record using the M600. We like the Polar Flow app. It's very much a lifestyle app on your phone, firstly delivering a report on your daily activities, but it lets you dive into your runs, check out your heart rate and pace from an activity as well as your route and other essential details.

Taking things further, the Polar Flow app has a calendar in it too where you can schedule workouts, meaning you can tap the watch and dive into the workout that you've planned. If you're training against a plan, it means you've got the information on your wrist, ready to get going. You can setup intervals, distance or time targets. You can also sync Polar training results and targets into your Google Calendar if you want and share the data with a couple of other services - Strava and Training Peaks.

Information is synced from the app to the web version of Polar Flow which includes a few more options and has more in-depth information. However, you don't have to use the browser at all during setup: you can connect the Polar M600 to your phone and do everything there, without having to use a PC.

There are a couple of bespoke Polar watch faces that will show you daily activity, so you can see where you are with your target at a glance, which help boost the fitness tracker side of the M600.

Before we get to actual sports tracking, the M600 wants to monitor what you're doing all the time. We mentioned that the Polar Flow has a lifestyle approach and this is has, breaking down your day into sleep, resting, sitting, low, medium or high activity.

With this in mind, you're presented with your progress through your day on the watch face. One of the elements of this is steps, which we feel is a little too enthusiastic about awarding you a "step". It's a hard thing to measure, as when we measured physical steps, the results seemed accurate enough, but in an average day in the office, we seemed to accrue many more steps through other movements.

Compared to Fitbit tracking, for example, it's a lot easier to hit your step target with the M600, suggesting that it's a lot more sensitive to movement than it perhaps should be. Steps isn't really an absolute measure, however, so if it's steps you're interested in, this probably isn't the device for you.

If you're inactive for too long you'll get inactivity alerts and these aren't just reminders to move, they get logged in Polar Flow, so you'll feel the enduring shame. If that's not a motivator, we don't know what is.

One of the nice aspects of Polar Flow is that it reports on your day, week and month assessing your activity and telling you what difference that has made to your life.

Press that button on the front and the Polar app opens on the M600. There are two sections, one to check your daily activity in more detail and the second to start recording a sport.

Polar gives you freedom to choose your sport profiles to suit the activities. For many this will be running, cycling or swimming, but there's a full range of sports to choose from, like badminton, dance, football or plain old walking, for example. That's great, because you don't have to compromise on categorising your activity. Want to record your dog walking? No problem. Want to record your Friday rowing session? No problem.

For outdoor sports you have GPS tracking, so there are different profiles for pool and open water swimming for example, which we really like and you only have to have the sports on your watch that you actually need. Don't want "other outdoor"? You can remove it. Head into the Polar Flow website and you get to customise your sports profiles further, changing the information you see on your watch, which it really clever.

Once you've selected your activity, the watch sensors fire up, looking for GPS and turning on the optical heart rate sensor on the rear. You can start the activity immediately, or wait for those things sensors to lock on, but again, with time being precious, it's sometimes good to get going without having to wait.

We've found the GPS to lock on quickly, however, so there's never really been too much of a delay in getting started.

During your sport, you're presented with a number of screens with relevant information, based on the activity you're doing. For running you get a main screen that's similar to Polar's other devices, like the V800. The M600 has the advantage of colour, so as you move through different heart rate zones, the colour of the HR readout will change too, for at-a-glance information. There's also clear indiction of pace and distance when running.

Swimming isn't as well served as it could be, with pool swimming lacking the option to detect lengths automatically like the Apple Watch 2 does. That leaves you with heart rate tracking and time, which is good enough. We also found that the flow of the water was able to swipe through screens, so we'd often stop a set in the pool with something different on the display.

With Android Wear automatically dimming the display, Polar has added the option to have the display always on. This means you can glance and see the stats without having to touch and avoids the problem of not being able to view the screen without an over exaggerated gesture. That will eat more battery, but if you're busting a gut trying to beat your 10k PB run, you won't care, you'll just need to keep an easy eye on your pace.

If there was one thing we'd want to boost the watch's sporting credentials, it's another button. We'd love a start/stop button, rather than having to use the display, but that's a minor thing. There's also no automatic detection for your activities, but sitting closer to a serious running watch we think that's fine: it will differentiate between activity levels in the daily tracking anyway, so there's no harm in selecting the sport you're doing for detailed tracking.

One of the great things is that the Polar Flow website provides a lot more information than you'll find on other platforms. It will give you an overview of your running progress, it will estimate how much fatigue you might be carrying over from earlier workouts as a guide to whether you're over or under training. You can also sign-up to training programmes, meaning there's a lot on offer, beyond your actual running stats.

There's a wide degree of variation in performance with the latest crop of sports gadgets, something that's seen widespread reporting about accuracy. The Polar M600 performs well in tracking via GPS, with some really accurate route tracking and good distance recording.

Polar has put six LEDs in the optical heart rate sensor on the back of the M600, aiming to ensure it's as accurate as it can be. Naturally, using the optional chest strap will give better results, but wrist measurement is all about convenience. The M600 performs fairly well, but we have seen some inconsistent HR results at times.

We've seen a fairly slow start at times, with the first 10 minutes or so seeing a slow build-up of heart rate, not quite reflecting the real rate increase. We've also had some runs where the watch would occasionally show a blank result, as though it wasn't recording, but it was. On checking the results afterwards, there's no sign of drop-out.

To verify what was happening, we tested it against a Garmin Forerunner 610 with chest strap. The Garmin was faster to respond to rate changes, more accurately reflecting the build-up of heart rate at the start of the run, as well as responding faster to some sprint sections we threw in. However, at the end of the run, both showed an average of 152bpm and both showed the same distance covered and same average pace.

So, although there are some anomalies with the results, that overall doesn't have a huge impact on the bigger picture of runs when using the Polar M600. Outside of running we've found it to deliver some good results and we're impressed it manages to offer a consistent result when swimming, for example.

That's where most sports devices would reach the limit of their functionality, but sitting on the Android Wear platform, the Polar M600 offers a whole lot more.

You get a full range of alerts and notifications and if you have an Android smartphone, this really is a first class offering, especially compared to the arrangement on some other sports devices. It's something that's offered by other Polar watches and some Garmin devices, but here you're supported by the Android community for your functionality, not just Polar.

We've mentioned apps and one of the aspects that the M600 gets from Android Wear is Bluetooth headphone and music support. You can connect any Bluetooth headphones you like, but music support is limited to Google's Play Music service and you have to download and sync that from your phone, which is a bit of a faff so it's worth only syncing music for running, but we love not having to carry that vintage iPod on the run.

Expanding out into other Android Wear highlights, you have Google Maps for navigation while you're connected to your phone, support for Ok Google voice controls, so you can speak replies to messages and so on. Then you have all the fun stuff, like being able to pause your Spotify music from your watch, controlling Netflix over your Chromecast, or getting Citymapper directions right on your wrist.

Although Android Wear has a bad rep from lacklustre early devices, the Polar M600 isn't one of them. This is a sports watch that benefits from a huge range of extra functions enabled by Android Wear, resulting in something fun and functional. In many ways, the Polar M600 is currently without compare.

Verdict The Polar M600 is a fusion of smartwatch and sports device. It takes Android's platform and laces in sports and fitness tracking functions, but maintains a balance that some devices don't manage. It succeeds in being both where others have failed. It feels like a proper Polar sports watch, boosted by the best of Android Wear. For an Android smartphone user, this is a device that's worth serious consideration. If you've been put off by Android Wear so far, this is how to do Android Wear right. It's not about bland presentation, it's about underpinning something more exciting. In this case, it's a fully-featured activity watch, especially good for running, that barely feels like Android Wear at all. The Polar M600 is currently rather unique. It's not only an effective sports partner, it's a great smartwatch too.

Writing by Chris Hall.