[Update - Sony has since responded to our waterproofing concerns. See here]

A few months ago we raved about how Sony had finally made a genuinely-great smartphone - the best Android-based model on the market in fact - but how things change in a matter of weeks?

The Xperia Z3's predecessor, the Z2 only came out six months ago and now here's its replacement. The two are actually so similar that I will focus this review on what's changed. Much of what was said in the Z2's review still stands, so if you are unfamiliar with that phone, I suggest you read that first.

Another change since that review is that there's now a very good iPhone - the 6 Plus model - leading the market. While many differences boil down to Apple versus Android (and the price!), the 6 Plus' camera redefined what we have come to expect from a camera on a phone. We raved about the Z2's camera but the handling, rapid focus and general operation, low light performance, metering, features and general accuracy of the iPhone's has lifted expectations across the market. With cameras now so important to a smartphone, we were particularly interested to see how the Z3 fared.

Design

At a glance, there's not a big difference between the Z2 and Z3. They are both classy, glass constructions surrounded by a metal band. However, the 1mm drop in all dimensions, particularly in thickness, mean the Z3 feels significantly more svelte. The nine-gram drop in weight is also noticeable. The actual spec differences for the Z3 and Z2 are, respectively: 146 x 72 x 7.3mm, 152g versus 146.8 x 73.3 x 8.2mm, 163g.

It still has a generous 3GB of RAM plus a microSD card slot and the Z3 is also available with 32GB of internal storage. The processor is a notch up on the Z2: it's still a Quad-core Krait 400 chip but clock speed is upped from 2.3GHz to 2.5GHz. The Z3 comes with Android version 4.4.2 while the Z2 hasn't upgraded past 4.4.2 yet.

However, of more interest is that the waterproof plastic flaps on the Z2 (which many people complained about flopping open too often) have been upgraded and now resemble significantly-more-robust panels.

This should make you feel more confident when making use of the waterproof features. However, as our tests discovered, be very wary of those claims.

Inside

The Z2 takes a MicroSIM but the Z3 now takes a NanoSIM. The screen on the Z3 is a smidge brighter but otherwise has the same specs at 5.2-inches and a 424 pixels per inch, Full HD resolution. All cameras are the same with a 2.2-megapixel unit mounted in the front and a 20.7-megapixel sensor at the back. The battery on the Z3 has actually dropped in size from 3200mAh to 3100mAh but don't for one second think that this is a bad thing.

Handling

The feature that jumps out is battery life. The Z2 could last three days at a push. The Z3 was still on 46% battery charge FOUR DAYS after its first charge under moderate use. That's approaching old-school Nokia territory and it will likely last even longer with the Super Stamina modes engaged. In the end we had to start putting major features like the camera through its paces so we had to recharge at this point. Sony promises a two day well-used battery life. This is accurate and likely understated. It's almost double what the Z2 managed and that (along with the HTC One M8) is still the next best in the market. By comparison, the iPhone 6 Plus just about lasts two days under moderate use.

The similar internals meant that we didn't notice much difference in performance. It's still highly-responsive and apps open very quickly.

Our main issues were with the camera.

Camera

Image quality is essenially identical to the Z2. However, now the market has changed and our expectations are higher thanks to the new iPhone. The Z3 is still capable of stunning quality when in good light, but now it's low light and handling performance feel poor by comparison.

Focusing still takes a bit too long (it isn't slow) and metering isn't as accurate as it could be. That means more shots are missed than we'd like. The iPhone somehow manages to meter and focus almost instantly (most of the time) whether in extremely bright, direct sunlight or virtual darkness. While initial exposures of dark subjects might look brighter on a Sony after taking them, closer inspection reveals that the iPhone is far better at capturing detail. Conversely, the Sonys up the ISO-rating to the point where grain is extreme and the picture near unusable, if it's in focus at all.

This was actually the best Z3 image we took of this scene which was akin to a moderately-lit nightclub. The iPhone 6 Plus managed much better all night. Click here for full resolution.

The Sony's camera is still good and capable of greatness, but the iPhone 6 Plus (along with its almost-steady-cam like video and outstanding super slow motion feature) has redefined what we expect from a phone.

The Z3 still takes highly-detailed and colour-accurate shots in well-lit environments. Click here for full resolution.

Waterproof?

But it wasn't all bad for the Sony which boasts some interesting robust features which, theoretically, allow it to be used under water at up to one metre for thirty minutes.

We got some great shots in our local pool, but not without major issues. For one thing, the screen constantly read water droplets as button presses so we had to constantly restart the camera by holding down the shutter button and using that to shoot with. Also, the headphone jack, which isn't sealed, kept registering that headphones had been inserted and all manner of options kept popping up.



You can't take pictures like this on many other smartphones. But then we don't recommend you do so on a Sony either as our unit packed up shortly after taking these.

Switching to video became impossible as the screen refused to respond in water. However, eventually it went blank altogether and didn't turn back on. While the rest of the phone works fine, we still can't see the screen after three days drying out. Basically it failed its waterproof test. We would not recommend you put this phone in water if you've spent hundreds of dollars on it.

Having run into this problem with other ruggedized phones before we were very careful about not submerging the phone too deeply and made a point of not doing so. All flaps were double checked too.

A closer look at the specifications shows that the submersion rating is only good for FRESH WATER. This is a major problem as Sony Australia has a great deal of marketing material showing its phones (and tablets) being used in the sea. Also, many of Australia's swimming pools are salt-water based. While it might be safe to get away with such waterproof claims in other regions - this is Australia! You can't ignore those details here.

We'll be pushing for more information from Sony in this regards. [Update: We did and Sony responded. See here]

Remote Play

A potentially highly-desirable feature of the the Z3 is its ability to hook up with a PlayStation 4 so that you can use the screen on the phone as a game screen by mounting it on a controller. We haven't been able to test this yet as the feature still isn't widely available. Early tests sound promising but we'll have to reserve judgement for now. Hopefully the feature will mature before the Z4 hits the market.

Overall

At around $550 [Update: this price comes from Shopbot.com.au. Some prices are for grey import models but all units bought from Australian shops carry Australian statutory warranties] for the 16GB Z3 it's the same price as the Z2. You'd be mad to upgrade from the Z2 though as it's only a slight incremental improvement with little noticeable difference beyond battery life. Nonetheless, Xperia has extended its lead in the Android phone market - the HTC One M8 and LG G3 whither under that battery performance. However, with the new Smasung Notes about to hit the market and with HTC about to announce something new, it still might be worth holding off a few weeks before buying one.

Is it better than the iPhone? Well, for many people, it'll be more comfortable to hold than the oversized 6 Plus but the camera on that is in another league and may well be worth any size-related annoyance. Beyond that it comes down to whether you want the intuitive simplicity and vast number of apps that come with Apple or the highly-customisable power that Android affords.

Oh, and price.

The Z3 can be had for almost half what the iPhone 6 Plus sells for. Therefore, as a value proposition, the Z3 wins hands down.

But is it still the best all-round phone? No.