My mini-review of the Xperia Z after using it for a few days, coming from Xperia V:
Display:
Like what most people mentioned, it looks slightly pale/washed out. But that is mostly due to the dark grey UI theme which Sony chosen I guess. Because whenever I view photo's/video or even play game, it still managed to display vivid colour. Blacks are alot blacker than the UI. The viewing angle was similar to the Xperia V though. No more yellow tinting issue which plague the Xperia V and S.(yay!? or is a heng/sway thing?) The high pixel density made the display so sharp and gorgeous. When playing 3D games like temple run 2, you can't even see the pixel.
It doesn't seem as bright as the V but very close. If you look close to the screen on highest brightness on the screen of Xperia V, you will notice that there is some strange texture(like cross hatch pattern) on the images, however, this is not the case on Xperia Z. The images looks clean.
Build quality:
The build quality of the Xperia Z was so amazing, felt very strong and firm when held in hand. Unlike the Xperia V when you hold tightly, you can hear and felt something moved.

All the flaps covering the port are much better now, easier to remove yet also easier to cover back.
However, I noticed that the Z seems to heat up more easily even when just surfing internet. It definitely heat up more than the V, the temperature can become quite high that it became uncomfortable to touch.
UI/Performance:
Some minor hiccup on the home screen occasionally, otherwise it is very smooth and responsive. Not sure what happened to those laggy demo set in the stores though. Games ran very smoothly
Audio performance:
Sounds pretty average until I turn on ClearAudio+

. Major improvement unlike the one on the V. This part is very subjective so I won't comment anything more. Earpiece tested was UM3X.
Camera:
Seems a bit better than the V when I compared side by side.
Battery performance:
Similar to Xperia V on the last ICS build, which is pretty good. Xperia V starts draining battery like crazy after upgrading to Jellybean and I can't use extended standby mode because it disables Whatsapp too.

But on the the Xperia Z, the battery stamina mode is an upgrade because you can now white-list apps that you want. Now I can finally leave it on standby without battery dropping at the same time!
Also, there seems to be some minor bug with the notification lights when you turn on battery stamina mode. It would not light up when receiving calls or sms except Whatsapp. But once you turn it off, the notification lights works as per normal again.
