The Dell isn't bad, but don't pay their retail. Rarely they will have it at 999, if you want it, do that.
The 12ms isnt TOO huge, because i read a lot of revies on all three of them and there isnt ghosting in any of them. Also dell's 12ms is probably black-white, not gray-gray like the other two.
Still though, you can't beat the Acer's price.