I've gone through 3 of these 27" monitors in as many weeks.
First was an Open-Box ZR2740W from MacMall - they repackaged it, and the mount-point of the base slapped the back of the monitor the entire trip, and damaged it. 1 Down. Didn't check the AG coating thoroughly, but it looked fine.
Next, I picked up a u2713hm from Newegg. This sucker is BEAUTIFUL... but it has a high-pitched whine on certain pages (seriously, you can't make it up, it's like a hummingbird drilling into your skull). No sparkles from the AG coating, tons of inputs... but that buzz.
I boxed it up, installed my 2nd zr2740w I got from Amazon warehouse (yes, I know, but I'm a slickdealer!), and sure enough, same damage. This time, the original foam just couldn't handle the pressure and broke through. When all is hooked up, pushing on the front bezel makes it fritz out. AG coating was like looking through a Coke bottle... back it went.
I re-hooked up the Dell, and can't notice the buzzing now. Burn in? Mount differently? My ears bleed and numb to the pitch? Dunno. I still get headaches using it all day though. :-(.
Noise info here: http://forums.overclockers.co.uk/...t=18455034