Display is crap on my unit as well. Bottom area is darker than the top area. Nokia service center people cannot 'see' this issue. Without any official support from the company, I am in no position to know if the issue is color calibration or faulty display panel. Stuck with it now.
I get the feeling that the top half of the screen is lit more than the bottom. I replaced mine but the replaced phone also had the same issue which confirms my theory that it's a case of uneven brightness rather than the bottom part bleeding. The reviewers who said this is the best LCD display they have seen in a while should be fired immediately. The colours are washed out. I downloaded Screen Balance app. It helps calibrate the white balance; although at the expense of loss of contrast. I use it while browsing or reading content