I personally dont like buying expensive stuff off of ebay, buts that because i have had bad experiences with it. I agree completely with everyone who says build. That PC looks nice at the beginning, but you can see it has some pretty crappy parts in it.
I noticed lower on the page that the same seller is selling "best gaming PC ever" for $2500.
It is soooo overpriced. You only get 2 6600GTs with it
. So that seller is probably not too good if he is saying that his other stuff is "the best ever" when it is not even close.