RE: the XZ3 a few thoughts.
So, the XZ3 is the first Xperia that does not support Sony's theme engine so any themes out there now for other Xperias won't work on the XZ3, unless you just want the wallpaper from the theme...so that is lame.
The Audio sound from the speakers, screen, feel and aesthetics of the device are top notch. The screen naturally is on the blueish side, but the display calibration settings let you take care of that easily. Dbl tap to wake, the full blown AOD, and glove mode are super features too. The Camera UI is revamped here which is cool I guess, but I never used the old UI. To me the pics are on par with the other flagships and surpasses some of them. It has EIS only and it does a great job with it. The OS software needs a bit of touch up though from my perspective. It stutters at times during transitions or when engaging things in a system app. Even seems unresponsive to touch sometimes, but my hands are used to working with my 950 XL, so I don't blame much of the touch issues on Sony. Could be too because I have glove mode/sensitive touch turned off maybe. In my book this device is a winner in a lot of areas, but it lacks the headphone jack which I use periodically, so I could never own it and keep it around as a daily driver. Even though it has the adapter dongle, it would not be the same and it is inconveniencing. However the jack lacking is not a total loss I suppose.