The problem with Dells return policy - at least according to much i've read about it on the interwebs - is that they indeed have a pretty liberal policy regarding returns, but you seem to be almost guaranteed to receive an already returned (i.e. not new) display...
I've found this out because i wanted to swap out my U2711 which has some issues when it's warm in the room - it might just go blank for a few seconds and then go back on again...
However since that is quite seldom (sometimes once a week, sometimes 3-4 times in an hour and then returns to normal) i've refrained from returning it cause one could get an even worse model - or so i've read..
http://accessories.us.dell.com/sna/sna.aspx?c=us&cs=19&#...
tl;dr: full replacement within even just 1 bright pixel if the display is an UltraSharp (IPS), same dark pixel policy as rest of their monitor line.
This is better than even Apple's policy. Long story short I think I'll be buying Dell monitors for the next while.