If home defense is involved, then reliability is the most important thing.
The edge in reliability would go to the USPc.
Make absolutely sure that anyone who has legit access to it is familiar with it's operation, and has shot it enough to be comfortable in it's use.
It is a good weapon, it will serve you well.
My particular H&K USPc in .45 is more accurate than either of my CZs or any stock BHP that I've had the pleasure to shoot.
I personally prefer .45 over .40 because the recoil is less with .45 (Slow push, less slide velocity, lower pressure, etc.) and the gun is a hair bigger, but not too big. I do realize that I'm giving up two rounds, but that's ok with me.
It ties with my SIGs in accuracy, and I like it's versatility better.
The BHP would have the edge in ergonomics (Better grip angle, pointability), capacity (Pre '94), and a slight edge in size (Slightly longer sight radius, etc.). It would also prolly have less felt recoil in .40 when compared to the lighter polymer-framed H&K compact.
I'd guess that the full sized USP in .40 would have similar recoil as the BHP, but I have no basis for that opinion, having never shot them side-by-side in the same caliber.
Both would require similar time to get familiar with, and get confidence in.