JDI type 1 - AH-IPS (this was used for the ZU)
JDI type 2 - VA (Xperia Z/ZL leftovers)
Sharp - VA (Xperia Z/ZL leftovers)
Samsung - S-PLS (Will only be used after all the VA panels are used up)
Sony is using up the remaining inventory from Z/ZL and mixing in some AH-IPS panels. Once all the VA panels are used up Sony will only use AH-IPS and S-PLS panels.
This would explain why some prototypes and production units have outstanding displays and some are just like Z/ZL.
1) According to gsm-arena
Brightness 580 cd/m²
Black level 0.38 cd/m²
This is an IPS panel like on Xperia ZU.
Verdict: Much better screen quality.
2)According to hi-tech.mail.ru
Brightness 488 cd/m²
Verdict: same poor panel as on Xperia Z.
3) According to ixbt.com
Brightness 460 cd/m²
Verdict: poor screen.
Pixel arrangement 100% same as on Xperia Z.
And pixel arrangement on ZU (IPS) for compare:
4) Thanks babylonbwoy for link - French site Les Numeriques tested the Z1 (lab test), they says that the panel is MVA Technology (according to them viewing angle will always be worst than IPS just du to this), and their test shows
Brightness 500 cd/m²
XZ1 test http://www.lesnumeriques.com/telepho...6826/test.html
XZ test http://www.lesnumeriques.com/telepho...5135/test.html
So, don't buy first party or go to local store and try screen on hands.