Great comparison. This is tough for me. Chipper is one of my favorites ever, and my 2nd favorite 3B ever (Rolen), but I have to give the slightest edge to Brett here. Brett was the better fielder and, at the end of the day, that's what I want more out of my 3B. Brett was good enough with the bat that I will try to make up what I lose with him at another position where defense is not nearly as important, like 1B or LF. Overall, Brett had the better career in terms of WAR no matter which way you slice it, and the edge in defensive play earns him the nod from me.
This is nothing for Chipper to be ashamed of. George Brett is a hell of a comparison, one which any player should be honored to have, and not expect to win.