Reviews I have read, and only a couple, say its as fast, close to equal.
Also there is the details ,system the card is tested on, type of test, type of benchmarking, and so on. These details can change the output (or benchmarking)of a card very fast.
I was thinking of a new video card and still am. I was looking at the 460 vs 6850. There is so many charts and benchmarks, some say the 6850 is better, then others say the 460 is better, while some say they are about equal.
Actually as far as the nvidia vs ati and which cards are better I could care less. I think the same way as the Intel vs AMD.
Whatever trips your trigger.
Good luck with your new cards.