When Comparing an H&K to a Berretta, to a SIG, to a Glock to a S&W
If you are talking same caliber and same frame size (Sub Compact, Compact and Full Size)
It would be like comparing Ford to Dodge to Chevy to Toyota. A pick up is basicly a pick up. Each has it's fans and followers, the same with handguns.
All have neat features, something unique, and all are reliable.
Figure out what you like, What features are important to you (ambidextrous, Decocker, safety, double stack mag, night sights?), what fits in your hands, and what fits you budget (remember in the budget to include ammo and range time as well as the other items you may want like leather, spare mags, cleaning supplies and the like)
I have a buddy that will spend every last $ of his budget on the gun and not have anything left for ammo or range time to use and get good with the handgun.
Personally I am a Sig Fan. I like the H&K guns but find the USP series a little chunky, but they work well and have neat features. I am not a Glock Fan - Great guns but they do not fit me and I have a hard time pointing them. I do have a S&W that was Glock based but the frame is at a different angle and I can point it to line up my sights.