I've owned 3 Glocks in my former, misguided life, a 19, 22 and 23. They were all accurate, and reliable for the most part. I never had a jam in either of the .40's, but the 9mm would jam occasionally. I hated the grip angle of them. It just doesn't feel natural to have to break your wrist that far to aim. I'm also a reloader, and I never felt comfortable with the unsupported chamber and not having the ability of shooting cast bullets safely.
My friend has an HK USP45C, so it's not exactly the comparison you are looking for. But, I thought it was a well built gun, but ergonomics just didn't feel quite right to me. Not bad, but just a little awkward.
Then it comes to the Sigmas. I was not happy at all when I was issued one at my former PD (where I left for another job in LE), until I started shooting it. I grew up on DA revolvers, and would have preferred to carry a revolver on duty, but it was mandated that we carry our issued sidearm. It was an SW40F, first generation which I put over 8000 rounds through. They were mostly 180gr cast bullet reloads with 6.2gr Unique powder. All you reloaders will know that Unique powder is VERY dirty and is about one small step up form black powder.
That said, I had one FTE with factory ammo during qualification. Other than that, never had a problem with it. Ergonomics on the Sigmas are the best out of them all, IMO. Many complain about the triggers on them, but if you can control a DA revolver trigger, you won't have an issue with the Sigma.
Since then, I've had 4-9mm, 3-.40 and one .357sig Sigmas of my own. Out of all of them that I've privately owned, absolutely no malfunctions of any kind. Those are a combination of 1st, 2nd and currently produced "Enhanced" series, too. In the currently produced Sigmas, they solved any problem, even the almost non-existant ones. Improved feeding and ejecting, loaded chamber indicator, tight tolerance striker assy and an equipment rail. You can't beat them for under $300!
I have a thing for enough mags for my guns, too!
I've never qualified with anything less than 100% with any of my Sigmas, or my Glocks, or my S&W revolvers either.
This group is my SW9F, SW9VE, SW40VE, SW40G and SW357V, along with a few of my mags. The SW40G usually wears the Streamlight M4 as my house gun, too.