Upload & Sell: Off
I'm using the U2410 and the 2412U in dual setup. Of the two my U2410, which is quite similar to yours, is the most uniform in full white screen by far, because of the CCFL backlight. Your U3011 uniformity looks even worse than that of my 2412U with LED backlight.
Why not return it to your dealer or DELL directly by using DELLS 3 year pick-up and return policy for Ultrasharp monitors. Your screen does not seem to be within the tolerance margins concerning screen uniformity (based on the picture you posted). Good luck!
ps. my screens are not calibrated, U2410 adobe RGB, 78% brightness, 66% contrast.