Software: Nothing to See Here
The best way to describe the software on the Sony Xperia Z2 is "interesting". There's certainly a few things that Sony does well in this aspect of their flagship handset, but there's also some things that haven't quite reached an acceptable standard.
Out of the box the Xperia Z2 is running Android 4.4.2 'KitKat' topped with Sony's custom skin. If you're currently rocking an Xperia Z1 that you've updated to Android 4.4, the Xperia Z2's software will be very familiar to you, although there are a few extras to be found. It's not surprising to see few differences between the Z1 and Z2 on the software front, as both are very close hardware-wise, too.
While many other OEMs have updated their software skins for 2014, Sony has stayed relatively stagnant, causing the age of their UI to really show up against other offerings. Compared to stock Android, the skin on the Xperia Z2 is fairly 'light', however there are some seriously strange interface and design decisions that are actually a regression compared to previous iterations.
The mix of flat elements and gradients isn't all that visually appealing, and the interfaces of basic apps such as Calendar, Messaging and Contacts are bland. A range of other apps, such as Gallery and Walkman, have received sidebar-centric updates which allows more content to be displayed on the screen, but this introduces a certain level of obfuscation to the interface.
Design is, of course, very subjective and I'm sure some Xperia Z2 buyers will love Sony's interface, but personally I feel that an overhaul of Sony's design language is needed in the next major smartphone they release. Luckily the design rarely hinders functionality, which in some respects is more important than the visual design elements of the software.
Several apps on the Xperia Z2 can be described as "skinning for the sake of skinning", adding a few minor features here and there while mostly just changing the design of the stock Android app. This selection of apps includes Contacts, Calculator, Alarm & Clock, and Messaging, which are all regular candidates for simple skins. Luckily if you're not a fan of the Messaging app, for example, you can switch it out for a different app - such as the Hangouts app used in vanilla Android 4.4 - quite easily.
Calendar has been notably improved since last I used it on a Sony device. The sidebar is a nice way of collecting extra options, while the inclusion of weather information for the upcoming week makes it easy to plan weather-related events. All of this is complemented by Facebook-integrated birthdays and a clean interface, making it a Calendar app worth using over the Google version available in the Play Store.
Many of the media-centric apps have enough features to satisfy, without being overly impressive. In the Gallery app I'm not a huge fan of the interface while viewing individual images, but the folder view is great and the sidebar assists with navigation of local storage and connected devices. You'll find the Movies app useful if you're tied into the Sony ecosystem as the home screen is basically a Sony Video Unlimited store, but it can also be used to launch personal videos, just like the Gallery app.
Walkman is the go-to music playing app, which again integrates Sony's homegrown music streaming and purchasing service, Music Unlimited. The transition is seamless between Music Unlimited and local media playback, and the extra data provided through Sony's service can be useful. However at the end of the day you'll probably just use it to play local files, which it does well enough, or you'll skip over it entirely for your favourite music streaming app.
The general layout of the home and lock screens, plus the widgets that accompany them, are typical affairs that are unlikely to excite regular Android users. If you click on the Recent Apps button in the navigation bar you'll find a set of apps that can be launched as floating windows, which are occasionally useful although I never found myself using them on a regular basis.
One area where Sony has made the interface worse is the notification panel. Previously, the simple pull-down panel would have a large area for notifications with a selection of quick settings toggles towards the top: it was simple, effective and visually pleasant. With the Xperia Z2's software, the sleek look is gone, replaced with a tabbed design that sees all quick toggles shunted under "quick settings".
Not only does this pane look amateur, the quick settings section isn't a huge upgrade over what was included previously. You can edit which options show up here, but the button to edit is in a weird position that I'd normally associate with the shortcut to the full settings screen. This meant that I continually pressed Edit meaning to land in the settings app, which is certainly annoying.
The actual settings screen comes with some interesting features, most of which are contained under Xperia Connectivity. In here, you can sync a DualShock 3 controller with the handset for mobile gaming, you can set up a media server, and you can also mirror your display to other devices. Sony hasn't skimped on features related to interconnectivity, that's for sure.
Other features to call out include the ability to select which system items to display in the status bar, limited motion controls, and a few Xperia themes to choose from. On the Xperia Z2, there is certainly no shortage of bloatware applications. Third-party navigation and photo editing tools are inexplicably bundled despite the phone also having first-party solutions, plus there's a wealth of other crap including Sony Select, Socialife, News & Weather, a dedicated Support app that is just a web portal, Update Center (which is already in the settings), What's New, and Xperia Lounge.
There's a range of second-tier bloatware-like apps as well, which may be useful to some people, but could just as easily have been left for third-party apps or Play Store downloads. TrackID is useful for identifying songs, but there are plenty of alternatives available, while Sketch is a basic drawing app and the PlayStation app is only really useful if you have a PSN account and Sony console. Oh, and there's also the PlayStation Mobile app, although I've never been particularly impressed with the range of exclusive games on offer.
I'm not specifically singling out Sony for some questionable app inclusions on their flagship handset - all manufacturers do it to an extent - but it's disappointing to see a lack of quality, exclusive apps bundled on this phone aside from the basics.
As for the keyboard included with the Z2, the swipe feature is decent and effective, although if you prefer typing normally as I do, the layout isn't great. The prediction engine isn't good enough to compensate for the small spacebar, which left me consistently missing it and running words together into a jumbled mess. Either use it through swiping, or download a third-party keyboard like SwiftKey.