I have both. My USP 9 extractor broke at 8k rounds. My 92FS (& G slide to go with it) has over 19k rounds on all original springs, even magazines and it still runs like a top. It had 2 failures to feed from a single ramline magazine (which I only used once) and has otherwise been flawless. The USP has failed to feed once, and failed to fully chamber one other time and sits at about 12.5k rounds now. I will without hesitation use / carry both.
If I were you, and I were sentenced to only one gun, I would consider the following.
Shoot them both. Not just with Winchester white box & CCI blazer, but with defense loads you would use for personal protection. They have to shoot well IN YOUR HANDS for you to bless them, regardless of what keyboard commandos here might think
Have you tried the PX4? If not, try it, you just might like it. They can be had at a bargain still...
If you want night sights, advantage HK (unless you're thinking of a 92G-SD, or Elite 2) since the HK slide is dovetailed, the Beretta 92FS is not. Some models do come with Trijicon inserts though...
Trigger: Variant 1 HK / Beretta 92. Slight advantage to the Beretta IMO.
One nice thing about the HK - it can be reconfigured to the LEM trigger, which is very nice, or a variety of other configurations, DAO, SAO, decocker only.
Magazines? The Beretta mags cost half what the HK mags cost.
Parts? - you have to be an armorer to get HK parts. BUSA will ship most parts direct.
weight - 'advantage'? depends. For H/D? Beretta - extra weight helps keep the muzzle down w/ defensive loads. For carrying? HK...
I suggest you give them both a try at the range, and buy a model of the one you shoot best.