If you read maximum pc magazine, they just reviewed both cards in the november issue. The STB got the Kick Ass product award, because it has better tv out control and d3d/opengl control applets. Both score almost the same in all benchmarks, but the stb implements the tv out better, and gives control for settings for opengl and direct 3d games. If these are not important to you, just look for the one that is cheaper (last I saw, they were the same price). But if either of these are important at all, get the stb card. It also has a longer warranty, but that doesnt really mean much in the video card industry...
Collinj