Your friend probably drank the Glock kool-aid and is making excuses.
I've owned both Glocks and H&Ks (no longer own any Glocks) and can say with absolute certainty that H&Ks require no more maintenance than a Glock, which basically just consists of a few drops of oil on the frame rails and the barrel/barrel hood. As far as parts breakage goes, I think you are actually better off with the H&K. The Glock's plastic guide rod alone is more prone to breaking than any part on the USP.
If your friend unnecessarily detail stripped his weapons, then yes, the Glock is much easier to detail strip than a USP. However, detail stripping is totally unnecessary unless you have 20,000+ rounds down the pipe and want to inspect every single part. Even then it's not really needed. As far as routine maintenance and cleaning goes, the USP requires no more effort to maintain than the Glock. If anything, it requires less. I say this because my H&Ks can go several range sessions without cleaning and still don't skip a beat. I can't say the same for the Glocks I used to own.
As far Comedian's firing pin breaking, I'm going to guess that it was a USP with the older style firing pin/firing pin block. There have been a few instances where these have broken with insane amounts of dry-firing. However, several years ago H&K replaced it with a newer and stronger firing pin that isn't as prone to breaking with excessive dry-firing. (Snap caps are a better idea anyhow.)