has managed to get its hands on the new 8800 GTS 512MB based on the G92 core and did a review. According to the review, this card is just right, better then ATI's Radeon HD 3870 and Nvidia 8800GT, and not much more expensive.
Tweaktown claims that the new 8800 GTS will not face the same availability issues as the 8800 GT. Suppliers have ordered their stock and the card should be available on December 11th. The card should end up costing about $50 to $100 USD more than the 8800 GT, but since supply was short 8800 GT's price went a bit higher than the MSRP, so both of them could end up at almost the same price.
The 8800 GT will probably continue the battle with Radeon HD 3870, and the 8800 GTS 512MB is the new sheriff in town. It might end up being the best buy for Christmas. ATI's Radeon HD 3870 is still a good card when you consider that it has a price which is even below that of the 8800 GT, but if you want a good card and you don't want to throw your money away on a 8800 GTX or Ultra, this is the card to go for, at least according to the numbers in Tweaktown's review.
You can find the review here