Absolutely NO WAY to tell who's the best at this juncture... A better question is which QB starts week one. The Bills, at least have some options. Rex, on the other hand, simply CANNOT put Sanchez out there week one against the Buck-o's. I've never thought of Sancho as a bad QB. However, the lack of confidence created by the Tebow torpedo will have lasting effects on his performance.
I expect that Geno will be the undisputed starter by the third pre-season game. Whether or not he can hold onto the Job is another story... For now, the Jets are primed to be the worst team in the AFCE, and I'm enjoying that.