I haven't really kept up on the Nvidia side of things but when I read this article I was very suprised on just how good these cards are
. Mostly I was shocked at how good the gts did compared to the gtx. At 1920X1200 no AA/16AF the cards were very close in performance. It was only when AA was turned on there was a significant performance difference. Anyways here is a link to Anandtech's review.
http://www.anandtech.com/video/showdoc.aspx?i=2945&p=1