S-Ranger,
Hello! I have each of the guns you're asking about. I actually like all three (P220, USP .45f and USP .45c)...
The USPf .45 is big. The grip is just a little too big (for me), to not feel as in control with it as I would like. It's not unmanageable, but is something to consider. (I'm 6" tall.) It is very reliable, though. I put the HK match trigger kit in mine.
The USPc .45 fits me a lot better. Slimmer grip and a smaller package (although not a real compact).
Personally, I hate gun locks. I wouldn't have bought the USPs, if I hadn't been able to obtain a small number of NON-locking "lanyard loop insert blocks". I replaced the offending parts and could then sleep better at night. (They're very hard to get, though.) A little german tinker absconded out of Europe to bring these parts to me. Many people died in the process... (Just kidding.)
I like cocked-and-locked, so the USPs have that appeal to me.
The P220. It's easier to carry than the USPf .45, but more on par with the USPc .45. I like it, too. Shoots good, points good and is super reliable. Mine is black. I had a SS model a long time ago, but didn't like the weight of it and sold it. I also prefer black or blue guns. I put a Sig short trigger in it and a piece of 3M non-skid tape on the frontstrap and it's ready for showtime. (The P220 has a smooth frontstrap, unlike the other P2xx models. The SS model does have some checkering on the frontstrap, though.)
I know you mentioned these wouldn't be for concealed carry, but for me, if it's in the car/truck, etc., there's a chance I may have to stick it in my waistband at some point, so it was a consideration for me. If you always have another CCW with you, that's not a concern.
I'm not a big DA auto fan, myself, but I've made an exception with my Sigs. (I prefer 1911s, BHPs and P7s.)
For putting in a truck, rucksack, etc., I like the USPs. They are more corrosion resistant than the Sigs.
I have to agree with you on the P7. It is one of the BEST CCWs. They are one of my very favorite pistols and carry very well.
Good luck with your decision.