I had both AMD and Nvidia cards. For AMD, I used a HD 6870 for a couple weeks and borrowed my roommates HD 6970 for extended periods. For Nvidia, I had a GTX 460 786 MB, GT 240 512 MB GDDR5, GT 240 DDR3, and 7600GT.
I MUCH prefer the control panel from Nvidia. I dislike that AMD's control...