The difference in the screen is pretty noticeable. I bought the K3 the day it was announced and posted some shots of both my white K2i and black K3 that I did on my scanner the day I got it. I never had any issues with the K2 and loved it, but I love my K3 even more.
Here are links to the pics that I posted:
https://www.mobileread.com/forums/sho...36#post1077436
https://www.mobileread.com/forums/sho...7&postcount=49