Test for you: http://www.lagom.nl/lcd-test/gradient.php

Before saying N900 screen is bad, go check your desktop screen.

Even my old IPS gaming display (NEC 20WGX) is not perfect in that test. Looks clean on 2490WUXi... and hence the price.

I'm more than happy with a current color depth since I can't really tell the difference for normal use case.