[Xperia Z2 General] sandulea:
It's strange how people get wildly different results with Lollipop. I'm on Niaboc's rooted version, debloated with TB, with Greenify hibernating most of my 60 installed apps, plus a few system ones, and I'm at 5h 30m screen time at 52% battery, down from 95% in 3 days. It's the first charge after flashing, and I rebooted it a lot at first, with TB restoring and uninstalling apps. My best with KK was 8h 46m on screen time, but this one looks like it's going to break the magical 10 hour mark soon enough.

As for usage, I talk and text a bit every day, but most of the screen time comes from browsing Flipboard, the browser and Locus (map app). Stamina mode is always on, and brightness is on auto, lowest setting. Wifi/data as required, but never on unless I forget it.

As for Lollipop, performance is great, interface is nice (nicer with the Aurora theme), sound is louder, maybe a bit better than KK, which sounded a bit muddy, I really like the notifications directly on the lockscreen. The baseband seems to get better signal, I used to get 1 bar in my office, now I get 3. The screen seems more responsive, I have a PIN lock on the SIM, and I can input the numbers in very quick succession compared to KK. The in-call quality, as others have mentioned, also seems better. I used to have other people ask me to repeat myself because they couldn't hear me quite well, now I don't anymore, and the sound on my side is clearer. The wifi turning on is a lot faster, thankfully, though with a caveat, mentioned below.

What I dislike:

-the dialer needs an extra click to bring up the keys, which is stupid. The contacts button is in the top right corner, which is a bit of a stretch. The previous setup, with the dialer/call log visible simultaneously, and with left-right slides for contacts and favorites, was more functional.

-the notifications area was destroyed. I don't understand why Sony chose to forego its customizations in this area in favor of a more stock google experience. No "mark as read" button on texts, and if swiped away they still count as unread, no long press for toggle settings, fewer toggles, smaller settings button. I am waiting impatiently for recovery, xposed, and Serajr's xposed module to bring this unusable mess to more functional levels.

-the camera, apart from faster launch and capture, hasn't been improved at all. For a device marketed with a focus on the camera, it's a real shame. Samsung was still updating the camera on my old Note 2 almost 2 years after launch, by lowering the noise, capture time normal, low-light and HDR modes and launch time. Also, there are apps on the market that take HDR pics at full resolution, yet the stock camera still can't do it.

-Unless you keep Scanning Always Available on, Wifi is even slower to turn on than before. My friend's LG G2 mini's wifi turns on so fast that you can't even close the notifications before the icon appears, whereas this one takes up to 20 seconds now. I have to do some tests to see how "Scanning always available" affects battery life.

Conclusion:

The first time I flashed it, I felt betrayed by the diminished functionality of the dialer and the notifications area, and the lack of xposed support and camera improvements were too much. However, recovery and Xposed are definitely coming sooner or later, I can get used to the quick toggles and dialer, and it's just a better ROM than the previous versions KitKat. I think people with strange issues had problems when flashing it, I flashed it twice and wiped everything beforehand. Even though I restored 50-60 apps with TB, I had no issues at all.