Both are undoubtedly good guns but, in my opinion, the 1911 ranks way above it for better ergonomics, follow up, and trigger control. Just to give some insight, I have been shooting the USP 45 Std since 1998 and now exclusively shoot SA 1911 (TRP, MC Operator, and Custom). The USP that I currently have has a LEM trigger installed without the safety and decocker (Variant 7). Do I trust it, yes, but can I shoot well enough with it, yes, but does it handle as well as my 1911, no. Do I trust my 1911, yes - why, they have worked fine out of the box and had no issues yet besides changing out springs in the 47D magazine. Everyone writes about reliability and durability testing, but in truth, most of us will never put it through its paces as do the guys who are actually out there doing the deeds that needs to be done to keep us safe, be it CONUS or not.
I will say that I do not baby my guns, nor are they safe queens. In addition, I do not clean my 1911 after every session. I will at times, just because I maybe lazy, tired or just want to see when it chokes, not clean it for several thousand rounds. I have seen my MC Operator get sluggish when I work the slide but when I shoot it, it goes bang every time.
Darren