Currently I have two screens: LG LP125WF2-SPB3 and AUO B125HAN02.0. They have some differences:
1] Physical dimensions: LG is easier to fit in the lid
2] Brightness: 400nit (LG) vs 300nit (AUO)
3] Response time: 25ms (AUO) vs 35ms (LG)
4] Maximum PWM frequency: 10KHz (AUO) vs 1KHz (LG)
The price is about the same. Both panels are 6-bit (52% NTSC, 262K colors). There are also 8-bit panels (72% NTSC, 16.7M colors), but they are much more expensive and difficult to source.
Also, it seems that X230 is still affected by low color depth issue which is presumably caused by the bug in the display driver for Windows. Chinese blogger says that X220 is exempted
I was encountered with this trouble as many other people who holds the x230 laptop. However, x220 series will not be affected if it uses a modified driver provided by the inventor of the adapter. This bug will cause a 16-bit-like color output on the screen panel, such that the gradual change of one color will not be so smooth as it was. If anyone remember the 16-bit color depth on the earlier LCD panels, that’s the feel. The root of this bug lies in the display driver, but no solutions has been ever given till now.
I haven't yet tried to find this driver, but can confirm that this issue is present on X220. That's the case when Linux users are really happy
Regarding the keyboard swap: you are going to swap the keyboard bezel as well for the perfect fit. I don't see any disadvantages.