I use one of two different USP's.
My new (er) one started off as a Stainless V1. i installed the sporting trigger(match trigger kit) and fibre optic sights, and changed it to a V3 with a $12 part. (no external safety, as it really is not needed)
I feel I shoot better using a 124gr bullet at around 134 pf. (combat masters ammo)
I used to use 147gr factory ammo, but it is too hot for this game.
I find the mag release is fast for mag changes, as I use my trigger finger. however the magwell on the USP is flared very little. It just takes some dryfire practice to get that working well.
I use a
Speedsec, but use a Bladetech belt once in a while. I also have the
Bladetech dropped and Offset (DOH), which is a
good compromise between a
race holster and a secure belt holster.
For
mag pouches I use Gugas Ribas, but would also recommend the CR speed, and Freedom Ventures line of
JR pouches.