Re: 7970 CF issues
No argument that AMD's drivers could be better based on my past experience. I've seen some crazy stuff with them.. the most crazy being them dropping support entirely for my sister's monitor when I built a PC for her one time. She had the 2900XT, and after a driver update she could not even get anything on her display. We hooked up another display and it worked fine. It wasn't the monitor, because we swapped it out on another machine and it still worked fine. The new driver just dropped support for her monitor.
Then I've experienced some XFire scaling issues on my HDTV like I did with the 4890s, as well.
Nvidia's not perfect either, though. Remember G80? Nvidia kept XP users limping along on what was practically a beta release driver for the first 4 or 5 months without releasing a proper driver until R600 came out.
Nvidia's driver support does seem to be a little better, but I've had issues with them both in the past. Just comes with the territory of having so many different configurations for ATi/Nvidia to have to account for.
i7-2700k @ 5.0 GHz
Nvidia GeForce 570 2.5GB Tri-SLI
Asus P67 WS Revolution (Tri-SLI)
OCZ Vertex SSD x 4 (Raid 5)
G.Skill 8GB DDR3 @ 1600MHz
PC Power & Cooling 950W PSU