This is some of the stuff I was hoping to see....or rather, hoping wouldn't exist but wanted to find out before making a purchase. As a novice, I'd assume a 75 from the early 90s would use the same basic parts/magazines as the newer ones, but if not, that becomes an issue for maintenance and upgrades in the future.
As for the Combat 85, I'd be interested to hear more about what makes it such a good option. The CZ webpage doesn't offer much, just saying the 85 is the ambidextrous version of the 75, and the Combat has "some additional features. The CZ 85 Combat features a fully adjustable rear sight, extended magazine release, ambidextrous slide stop and safety catch, drop free magazine and over travel adjustment on the trigger".
Actually, the P-07 looks neat, too, and with most engagements in USPSA at close ranges, the shorter length shouldn't affect things too much. On the other hand, there are some long range targets that a longer weapon will engage more accurately, and the light weight may make it a little slower to manage on follow up shots. Different trigger system, too, which may or may not be a good thing.