Greetings,
Haven't posted here in a while. But, I have a USP45F, G19, G17, and had a G22. I love my G19 and G17. Recoil is easy, but hey, it's a 9mm, and although they require more focus of concentration for me to be accurate with them, I really do like them. The G22 I had was a 3rd gen w/ the finger grooves which I can't stand. Also, I don't like the way the Glock handles the .40. It's a snappy round to begin with and you (or at least me) feel the recoil more exagerated than in other .40 platforms I've fired (Sig 226/229, CZ75, Beretta 96, HK USP40C). Regardless, it really comes down to personal preference. In reality, they are both excellent handguns.
Having said all this, the USP is the one gun I would absolutely keep. It is without a doubt, my favorite platform in any caliber. I love the controls, the ergos, and the accuracy is OUTSTANDING!!!! I agree with what another poster said in that the USP's slide seems to move slower, especially as compared to the Glock. However, I can shoot this gun better than anything else I've shot. It has never ever hiccuped, can't say the same for the G17 & G22 that I've owned. My next pistol is a USPF in either 9mm or .40.
Shoot them both. Shoot them again. When I first got my USP, I was dissapointed at the range. I was shooting consistent groups, but they were a good 2" below the bullseye. I dry fire practiced a lot for a week, went back to the range and all was heavenly at the range. Accuracy was great. I've always had a hard time w/ Glock triggers, but maybe that's just me as a lot of folks swear by the Glock. Again, either pistol is great, it's all about personal preference.