They all run at 1050 res, all have DVI, all have speakers, etc. etc. etc.
Do you need USB ports? Many of them have added ports on them.
As long as the specs on the screens are comparable, I'd say go with the best price. Yes, there will be differences in color profiles and display settings, all of which can be worked around. Response times are great, but in reality they don't always seem to predict how the screen will actually perform. Most current models all perform well enough.
Do they all have similar policies regarding dead pixels? That's a common complaint, and is also a compelling reason to buy one off the shelf so you can look at it before taking it home.