The word that best describes the software you get with the Xperia XZ2 is 'stock-ish'. Unlike Samsung, Sony was among the first companies to adopt Google's software navigation buttons, and those are still present of course - in fact, the geometrical shapes aren't hollow, they're even filled like they are on Pixels. We were under the impression that this design flourish was meant to be exclusive to Google's handsets, but apparently not.
Sony's launcher even comes with the Google Feed to the left of the leftmost home screen page. That said, it does have more options than the Pixel Launcher - you can choose between various grid and icon sizes, sort through the app drawer in multiple ways, and pick whether you want a button to take you there or just a swipe up from the bottom - the latter, again, inspired by the way things work on a Pixel.
This isn't an Android One device, however, so you do still get a few Sony apps and third-party preinstalls such as Amazon Assistant and Prime Photos. If you're the type of person who likes to have as few apps as possible installed, then this won't help achieve that goal. But with 64GB of built-in storage, the XZ2 has plenty of space to house even a few hundred of your apps on top of the built-in ones, which are pretty easy to ignore.
The stock-ish feel is present throughout the user interface, but not everywhere - the connectivity icons are decidedly not stock, going with the 'multiple lines' design, for example. The quick settings area functions exactly as it does on a Google phone, and Sony thankfully has left Android's notifications alone too.
The multitasking rolodex is stock, except for the fact that the 'clear all' button shows up at all times, and not just when you scroll all the way up. The Settings menu adheres to Google's general concept for Oreo, but it's got colorful icons and is arranged slightly differently. No big redesigns here, though, such as tabbed navigation.
Overall, the software experience is pleasant. It's true that Sony's generally been faster than others when it comes to issuing updates to new Android versions for its top of the line models, so for Android P you probably won't have to wait more than 3-4 months.
Since the phrase is starting to quickly change its meaning in the mobile world nowadays, we want to use it before it's too late: performance on this phone is 'top notch'. That's the best way to describe the XZ2's performance, day in and day out. The phone is always incredibly fast and doesn't slow down at all, no matter what. It never got uncomfortably hot either.
You can definitely tell you're holding a 2018 flagship, every moment you interact with the XZ2. Maybe that doesn't necessarily show in terms of its design, but rest assured that software lags are not something you'll encounter.
And now the much-anticipated note on the hard-to-define concept of 'smoothness'. For the first time in the short history of our long-term reviews, we have here an Android device that reaches the level of smoothness of a Pixel. Well, almost, the XZ2 isn't all the way there, but it's the closest of any phone that has been put through the long-term review process.
That's high praise because even at this point in time there are competing flagship handsets that can't match the original Pixels from 2016 in this regard, not to mention their successors. We assume the Snapdragon 845 SoC used by the XZ2 has something to do with it, but it's also clear that the company has focused its software development on this concept of 'smoothness' more than its competitors.
'Smoothness' is hard to describe in words but very easy to understand once you have a Pixel in one hand and another Android phone in the other, and you perform the exact same actions on both in parallel. If you can't do such a head-to-head test, then you might not even know what you're missing. This is one of those things that fall into the 'once you know about it you can't stop looking for it' category.
The battery capacity of 3,180 mAh isn't a lot, but the Xperia XZ2's battery, chipset, and software combine to squeeze some impressive results from that unimpressive capacity. Battery life has been great with our use case involving around 16-17 hours off the charger each day, with most of the time spent connected to Wi-Fi, a couple or so hours of mobile data, and Bluetooth always on (with music streaming for 1-2 hours).
From 100% down to 0% we would have topped 8 hours of screen on time in one record-breaking day, but we chose to charge the phone when it was at 6%, as you can see in the screenshot below. Even so, we managed a very respectable screen on time number, a higher one than we're used to.
Undoubtedly, the Snapdragon 845's efficiency is at least in part behind these numbers. Overall, throughout our usage of the XZ2 as our one and only phone, we got at least 6 hours of screen-on time each day, which we think is nothing to scoff at. Obviously, if your use case involves a lot of time spent on mobile data, depending on the signal levels where you're at, the number will be lower.
That's normal, though, it's just the way things work, for now at least. In the end, we'd say you're likely to be satisfied with the XZ2's endurance, and if you aren't, there's always Sony's Stamina Mode - which you can activate to make the phone last even longer.
You may even see a notification about it from time to time, urging you to turn it on to get an hour or two more out of the device than you would normally. We thought that notification was useful at first, but after seeing it every day for a week it became quite annoying. Anyway, it will probably help people who don't know what Stamina Mode is.