Let me get this straight:
1) You like the current gun you have
2) You have a good setup, with light, night sights, holsters, and four magazines
You are trading this gun for a gun which
1) Has a safety
2) Has only two magazines
3) You shot a similar version and didn't like it
4) Its 'refined'.
I have a USP. It's a fine gun, but not perfect. It can be limp wristed. The trigger isn't amazing (I'm thinking of upgrading to the match trigger). I feel like I don't shoot it as well as I could (but possibly that's just me making excuses). I have shot a glock. I did not like it. But since you like the glock, shoot it well, and have the accessories....i would not get the USP.