Ill echo the call to skip the USP and go to the newer p30 or hk45 pistols. USPs are monsters and a lot of slide moving high above your grip. That being said they are still a great pistol.
What the USP has over the newer HK guns is you can get a trigger stop on the competition trigger. The newer ones wont allow for it with the much nicer ambi mag release.
The DA/SA trigger does kinda suck. However its like anything. Practice with it and you are golden. The super light LEM version is very nice with a great reset and very light LEM pull.
You can find USPs on the cheap used. Heck we got some turn ins that were beat to hell. I ran 10,000 more rounds through the one i picked up before offing it. No telling how many rounds were through that beast.
In the end the grip is just too big for me so i went in a different direction. Dont fall for the HK hates you internet hate. They are very, very helpful and a good bunch of people at HK USA.