Whether you like it or not, there's little doubting that the Galaxy S5 was the star of the show at this year's Mobile World Congress. Samsung had the largest press event, the most crowded booth, and the most hype built up leading into the show. It doesn't matter if it's still plastic, if it's still running TouchWiz, or that it's still arguably one of the uglier flagship devices on the market - this phone obviously matters a lot. Samsung is going to sell tens of millions of these things a matter of months after they launch, and because of that, we're taking a special focus on the S5 during our MWC coverage.

As the person charged with reviewing the Galaxy S4 last year (in somewhat ridiculous detail), I felt compelled to take a closer look at the new software Samsung has created for its marquee mobile product.

Galaxy S5 Software: Generally

What's new in the new TouchWiz? A lot, frankly, especially in a visual respect. While I've read numerous hands-on posts claiming the changes to Samsung's UI layer aren't all that aesthetically dramatic, I'd have to disagree rather strongly. This is easily the biggest update to TouchWiz since the original NatureUX that debuted on the Galaxy S III two years ago, and arguably is even bigger than that in some respects.

While certain elements are very familiar (eg, the home screen isn't radically different), almost every significant piece of the UI has been touched or updated in some noticeable way. The "flat" aesthetic we'd seen unveiled initially on the Tab Pro series has weaseled its way into the S5, and I think the result is inarguably an improvement.

The notification bar is perhaps the area where this change is most dramatic - flat toggles, new quick shortcuts for S Finder and Quick Connect (which, unfortunately, do not seem able to be disabled), and a lighter theme overall simply make the S5 feel much more modern than its predecessor. The settings menu also now defaults to a grid, rather than list-based, layout, which I think many users will prefer. It's certainly more intuitive / easy to navigate than the tabs Samsung utilized on the S4 and Note 3.

Note: the video erroneously states Magazine cannot be turned off, but I later correct myself.

Other elements, like the app drawer, have just been cleaned up. Instead of having tabs up top for apps / widgets / downloaded apps, Samsung just uses a subtle 3-dot menu button and the top right, making the drawer look much less cluttered. Adding widgets is now done solely by a long press on the homescreen, which brings up a GEL-like 3-item menu along the bottom of the display, as opposed to Samsung's previous implementation, which brought up a menu.

The homescreen isn't radically different, but Samsung does dedicate the far-left pane to its Magazine interface, which is in many respects similar to both HTC's BlinkFeed and the Flipboard app. The Magazine homescreen can be turned off in settings, though, which I imagine is something many people will be quick to do. It was actually a bit choppy on the unit we played with, too, and was the only time the S5 really felt all that slow during our testing.

Speaking of performance, the Galaxy S5 is easily the fastest Samsung handset to date. Even compared to the Note 3, the Galaxy S5 simply feels more nimble and well-adjusted to rapid multitasking and scrolling. The units we tested weren't even on final software, so it's entirely possible there are yet more gains to be made in this regard. Compared to the Galaxy S4, which wasn't blazing-fast to begin with, and now feels a bit laggardly, the S5 is a major step up in the speed department.

So, all that business we heard about Samsung culling its content offerings and scaling back TouchWiz - it seems that many people perhaps expected too much here. The one thing Samsung has removed (though would not comment upon) on the Galaxy S5 is Samsung Hub - Samsung's movie, music, and television content store. Samsung Apps is still present, but the absence of Hub is simply too convenient not to chalk up to the rumors we heard last month. As for the UI itself, you're out of luck - this is still a very Samsung affair, and nothing I saw suggested to me that Samsung was in any way kowtowing to an alleged Google demand for a more "Android-like" experience.

Samsung's own apps have undergone various levels of transformation as well, with apps like S Planner (calendar) and the Browser both sporting flatter, more modern interfaces, amongst others. We'll save the detailed look at those for the review, though.

Galaxy S5 Feature Spotlight: Fingerprint Scanner

We had a chance to set up and test the fingerprint unlock function on the Galaxy S5, and while I walked away less than wowed, I will admit the feature does work as advertised.

Setting up the fingerprint reader is fairly easy - go to lockscreen settings and set it to fingerprint mode, at which point you'll be asked to set up a backup password (in case, you know, you burn off your fingerprints or something) as an alternative to the reader. Once you do that, you'll be required to swipe your finger of choice roughly 8 times (for me, it was more like 16) so that the phone can get a good sense of what your fingerprint looks like. Samsung claims up to 3 fingers can be stored, but they didn't demo the functionality for multiple fingers to us, unfortunately. Once the print is stored, simply turn off your display, turn it back on, and voila - you'll be prompted to swipe down from the bottom of the screen over the home button. I found it worked with my index finger about 80% of the time, maybe more if I was particularly careful with my swiping. It's enough to be usable, but not so accurate as to be anything close to foolproof - you do need to take some care in exactly how you slide your finger across the sensor (flat against the surface, not too slow, not too fast, etc).

The unlock function falls flat for me for one, simple reason: I still have to hit the power or home button and wait for the display to turn on before I can actually swipe. With Apple's Touch ID, the fact that it reads your finger in static position once the home button is pressed simply seems better. I'm not arguing about the merits of either technology in terms of accuracy, long-term reliability, or security, but the Apple solution is just simpler. Pressing a button, waiting for the display, then swiping does not feel like the future - it feels like an encumbrance.

Samsung does promise it's looking into expanding the uses for the fingerprint reader to things like your Samsung account and PayPal, so there's that. We'll have to see what the level of third-party adoption ends up being, but I doubt we'll be authorizing Play Store purchases with our thumbs any time soon.

Galaxy S5 Feature Spotlight: Heartbeat Monitor (AKA Pulse Oximeter)

With the Galaxy S4, Samsung made adding new and interesting sensors to their devices a priority - the temperature and humidity sensors on the GS4 were interesting developments that, while maybe of limited usage, did differentiate Samsung's hardware from the competition in a real way. This year, Samsung's added another interesting sensor capability, in the form of something called a pulse oximeter.

The oximeter is the transparent square on the left of the sensor cluster, below the camera.

The short of it is that a pulse oximeter reads your heartbeat by shining light through a thin cross-section of your body (eg, a finger) and then measuring the varying levels of light absorbance. When your heart contracts, arterial blood surges through your body, and this effect is observable all the way down at your fingertip. When there's more blood, more light is absorbed, and by continually measuring the amount of light absorption occurring at the observed area over a period of time, your heart rate can then be calculated (the accuracy of pulse oximetry isn't perfect, but it's pretty good). The basic technology isn't [remotely] new, but as far as I'm aware this is the first time we're seeing it in a smartphone.

Using the S Health app, you can measure your heart rate whenever you want, simply by putting your index finger over the oximeter on the back of the phone. You then can watch the graph of the oximeter's raw measurements fluctuate while it determines your current heart rate, and I found the feature quite reliable, and honestly just kind of fascinating. I'm not sure how useful it will be on a phone as opposed to a smartwatch or fitness tracker, but it's neat nonetheless.

And no, as far as I can tell the pulse oximeter does not actually allow you to measure blood oxygen levels, though perhaps an API could open up that possibility.

Galaxy S5 Feature Spotlight: Ultra Power Saving Mode

Our final feature spotlight for the Galaxy S5 will focus on what for many users will be a brand-new experience on their Galaxy S5s, in the form of Ultra Power Saving Mode. We know now that this feature isn't technically new - Samsung's had it on a few of its Japanese devices for some time now. But for Europe, the US, and the rest of the world, this is new, and it's actually quite cool.

Most power-saving modes on smartphones require you to do a lot of the work in terms of deciding just what you do and don't want to turn off, or just how much energy you want to save. This sort of defeats the purpose, in my opinion, of a power saving mode: I want to put my phone in a state where it will still function as a phone for calls, SMS, and email, but is otherwise using as little power as humanly possible while remaining practically usable.

Samsung's Ultra Power Saving mode takes this philosophy to heart. Switch it on, and things change - a lot. The first difference you'll notice are the colors - they're gone. The screen goes black and white monochromatic to save power, and brightness is greatly reduced. Next, Bluetooth and Wi-Fi are disabled. Fancy UI animations are turned off. You're also given a severely limited UI - Samsung actually turns off a bunch of services and disables communication / sync for the vast majority of your apps. You get access to calls, email (including Gmail), and SMS, as well as a few other, select apps. There is only one, basic homescreen. However, mobile data remains enabled (LTE is off, though, it's 3G only in this mode), so you'll still get all your SMSs and emails.

Samsung claims this feature is so effective at reducing power consumption that at 10% remaining battery life your phone will be able to last in standby mode for 24 hours. That's pretty incredible. On the unit we were testing, which had around 20% battery life, the estimate use time (as opposed to standby time) was around 7 hours, which is also quite impressive if true.

Obviously this feature will require some field testing, so there's not much else to say about it now.

Galaxy S5 Software: In Conclusion

My first look at the Galaxy S5 left me impressed. I believe that Samsung's increased focus on speed and restyling the UI are key to enhancing the user experience across the board. For all the TouchWiz and plastic jokes, the Galaxy S5 is indeed a very modern, competitive device. It feels new.

While Samsung hasn't exactly simplified the act of navigating and engaging its many various features and gimmicks littered throughout the OS, what it has added will undoubtedly catch the eyes of buyers. The fingerprint scanner isn't perfect, but I have no doubt it will be a big draw for consumers envious of Apple's Touch ID. Things like the heartbeat monitor and ultra power saving mode will also 'showroom' well - tell someone they'll get 24 hours out of the last 10% of their battery and you'll certainly get attention. Likewise, showing a phone monitoring your heart rate will definitely raise some eyebrows.

We'll have to see what Samsung's latest camera can do out in the wild, too - their fast autofocus claims are definitely appealing if true, and Samsung has always had great sensors in its high-end devices.

The Galaxy S5 doesn't do anything incredibly groundbreaking compared to the competition. it doesn't look all that much different (many would argue it looks worse). But what it does do is bullet-point itself above and beyond its predecessor with ease - and that's really what Samsung needs to keep increasing its market share at the high end. I look forward to reviewing the Galaxy S5, and I have little doubt it will be anything short of "quite good."