I think it all depends on what you want to get out of shooting USPSA. Are you trying to compete for wins at Level II and above? If so, you're probably better off sticking with CO and saving up for a 2011. Do you only shoot Level I matches and only compete to have fun? Then shoot whatever fits your budget and your personal goals. I shoot an Open Glock 17 (currently setup for minor) because 1) it's cheap 2) it's fun 3) it's versatile (can shoot USPSA, Steel Challenge, GSSF, local Action pistol matches, etc.) 4) it runs with no issues and the biggest reason...5) THE GUN IS NOT WHAT IS HOLDING ME BACK FROM BEING COMPETITIVE!
So in summary, I'm a fan of Glocks and Open Glocks but just be realistic with what you want to get out of it. You do not need a $3500 gun in order to have fun and be competitive in USPSA (even in Open).