I shoot a USP in 40. I was always reticent about getting one as I had always felt that the Glock and SIG's was too boxy for my size 6.5 hands but the USP seems to fit perfectly. I had always regarded the Hi Power as the best fit for my hand before that.
I like being able to hit the Mag release with the index finger of by strong hand, my grip stays fairly constant during reloads. The safety is easy to get to; the decocker took a bit of getting used to but is second nature now.
Both the DA & SA pulls are decent. Much better after a few hundred rounds. The DA pull is surprisingly good, feels like a nice Smith & Wesson revolver.
The one thing that sticks out is the fact that of all my pistols I have had the least FTF's and no FTE's, mechanically the thing has never let me down. Also no issues about shooting lead through the polygonal barrel with the USP.