I've used both Ati & Nvidia cards in the past few years and I lean quite a bit towards the Nvidia side. I've always just had better performance in the long term with my Nvidia cards vs. Ati, but again, everyone will always pick a side on the issue.

The 9800 is a good card for the price imo. Why do you say only EVGA or Asus cards? (I only ask because I read a great review at a couple of places last month around the Gigabyte 9800gt, which I've never personally bought a Gigabyte card, but ehh.)

I'd say Nvidia ftw.

Here is a couple links for reviews, Tom's hardware does a lot of reviews that aren't always the "super extreme $500 cards" which can be helpful.

GeForce 9800 GT Roundup (EVGA, ASUS, Gigabyte & Palit) - Hardware Canucks

Best Graphics Cards For The Money: Feb. '09 : January Review/February Updates - Review Tom's Hardware