I have a USPc in 9mm and a P2000 V3 in .40.
To me, the P2000 is the better pistol in regard to ergonomics, handling, reliability, and accuracy (not that I can hit the broad side of a barn, mind you).
Until I got about 400 rounds thru the gun, the USP had a few feed and stovepipe problems. Seems to be shooting fine now, but I just don't trust it. With about 400 rounds thru it, the P2000 has had no problems at all.
Being a lefty, maybe I'm not the best person to comment on handling and ergonomics. But I will say the swapable backstrap on the 2K is really nice.
Knowing what I know now, if I had to choose b/t the USPc and the P2000 I would pick the P2000 and never give it another thought.