Well fortunately the p7 has been added to the production legal guns. I'd suggest you try that instead of the USP 9.
The USP in general has a logn gritty DA pull, and a so-so SA triggger. The real disadvantages it has are a high bore axis, a lot of it's weight being in the reciprocating mass of the slide, and the dual stage recoil system doesn't like light loads. So you can shoot it for fun, but you put yourself at a disadvantage. Getting high C with it is no problem. B is probably doable. Beyond B, you are likely going to be fighting your gear a fair bit.
If the p7 is the m10 or m13, i'd say just drag that out if you are looking for fun rather than buy a new gun. But if capacity is less than 10 rounds, you'll be at a significant disadvantage. Reloads will be a bit of apin too with a single stack.
Maybe it's just me, but if I'm going to show up and shoot something less than optimal, the P7 sounds like a lot more fun, even with less than 10 rounds. Also from a social aspect, the p7 should start more conversations than a USP.
Plus it saves you several hundred dollars of gun.