Its amazing that XFX is giving away 6990s! I think the amazing parts about these cards are that with a 2GB frame buffer you can really pump up the AA to 4x, have triple monitors and still get a pretty steady 60fps which is unreal! If these cards are supported by XFX's warranty, all the better!!
I like XFX's double warranty, not many companies still do this and I applaud XFX for keeping it.
I like the 6990 because it seems like the best of the best at the moment. Amd's drivers can cause a headache here and there, but once you get it sorted out its amazing what performance you can get from amd's recent line of cards.
I'm currently using an xfx 4890 which has been working flawlessly for about a year and a half. The first thing I noticed about the xfx brand was the quality of the packaging and boxing it comes in. Very nice and stylish looking, you just know you are getting a great product. Still runs anything I need it to, perhaps it is time for that 6990 upgrade though.