The key is finding a vendor that makes the best circuitry to communicate with the GPU, and or one that has the features you want most.
Try http://www.tomshardware.com for reviews on pc hardware.
All those graphic cards out there confuse me. There are so many brands that carry Nvidia. I thought it was just Nvidia who sold the cards. what i came up with is that Nvidia makes the tecnology and then others sell it. so now my wustion is, which is the best company?