I can't vouch for the latest addition from ATI but I can vouch for the differences between ATI and NVidia.
I used to review harware on my own site for near 3 years. I'm Not partial. I was a 3dfx man.. Voodoo all the way. When the GeForces came out I moved to them.
On a lark I tryed the Radeon (it had TV out) the 7500. Wow. Even with all the settings I could possibly find turned to low, it honestly oudid the nvidia GEForce 4 in quality.
I then built a few computers for people who play everquest. Again, the 8500's quality kicked Nvdia in the pants. This time not only in qulaity of picture, but speed as well. The closst I have come is now the 9200? I belive. Wow, Still ATI is just look and speed wise kicken the pants out of anyone around.
One feature ATI is capable of that Nvidia isn't. One I need. ATI cards have had TV out for generations before Nvidia, and they are good at it, with both quality and features.
I can simultaneuosly view the same screen on both the computer, and the TV. Sure lots others can expand your desktop, lots others do dual monitors too. Not one card I have found allows you to do both at once except Nvidia.
I sit at my computer, and setup the movie(divx, dvd,vcd) resolutions, colors, etc. With the familiarity of a keyboard and mouse on a monitor, keepin' an eye on the TV's quaility, and picture. When I am done I pick up my wireless keyboard and mouse, and sit with the family on the couch.
The Nvidia line of chips won't display the same screen on both at once. You have to start the movie, then "drag it over" to the TV which is called and "expanded desktop". Its a b$*ch to setup for sure.
ATI has really impressed me with their latest generation of cards. Like I say, I'm not partial to any company, just whatever looks the best, runs the best and has the best features at the time. To me, ATI has nailed it in this generation of chips.