I got the 920 for a couple of months now, same as some users I have the issue of light bleed from the top of the screen. You can only see it if you look at it from a certain angle, you cannot see it if you look at the screen directly.
Well, I did go to a local Nokia Care Center, they said they don't consider this as a problem, but they can still order and replace the screen for me if I wanted to. Earlier this week the screen came in and they called me to get it replaced.
My question is should I get the screen replaced? A few people said to me that if the light bleed doesn't bother me, don't have the phone opened to replace the screen. The body design of the 920 doesn't look like the type that can open easily to change parts.
Anyway, if I do get the screen replaced, I'll also ask them to replace the battery. I don't know if it's normal, but the battery life is really not that great. I get about half a day, by late afternoon I've to charge the phone again. Basically I'm charging the phone twice a day, and no I don't have many background services running, and I don't have the wifi always on.
If you are bothered by this issue and they will replace the screen under warranty I don't see why you should not do it. I don't know if they will agree to a battery replacement as well though, but you can always ask for it.