Alright... i have a 1900XTX and i have to say that i have no regrets AT ALL! I have a friend who is a die hard Nvidia fan. He buys Nvidia no matter what they put out. So I've paid a lot of attention to the details in the reviews.
First off make sure you pay attention to the drivers a reviewer is using when they do their reviews. If you compare the benchmarks of the X1900XTX from HardOCP to the benchmarks of X1900XTX from Firingsquad, you'll see the results from the same card are very different because HardOCP used 6.2 Cat drivers and Firingsquad used 6.3 Cat drivers. I would have liked to see HardOCP use the 6.3 drivers cause i really like the way they do their benchmarks (not based on peak numbers).
Second, if you look at HARDOCP's review of the 7900GT, they compared it to an X1800XL instead of a 1900XT.... why? i don't know... would it be safe to say that the 1900XT would have out performed the 7900GT? Absolutely because the 7900GT beat the X1800XL by only a 4-10fps depending on the run.
If you notice the 7900GTX beats the X1900XTX only by a fps 4-10 depending on the game however, notice that the X1900XTX has clear gaming advangtages over the 7900GTX. What does that mean? It means if all you care about is fps, go with the 7900, but if you want the better quality picture at the cost of 4-10 fps, then go with the 1900. Now mind you, again i think the benchmarks would have been very different if they had used the 6.3 CAT drivers. I really believe the numbers would have been very damn close if not the same...at that point the X1900 would have had a clear advantage because it puts out a higher quality picture.
Now, to be fair to Nvidia, will new drivers make this card faster? Probably...how much faster? I don't know. Will it take care of the shimmering problems? I don't know...
For right now, ATI has WHQL drivers and is its obvious that they have very little of the shimmering problem that is noticed by Nvidia users.
As far as price, i think we are going to see the price of the 7900s go up today as the stock starts to run out. ATI X1900XTX on new egg is still in supply and under 600.00. A powercolor card comes with a lifetime warranty
Anyways, thats my take.