It takes too long to load mags.
As opposed to what? HK mags are about the easiest to load.
They dont take long to empty though.
Just out of curiosity, which SMG do you find better as an all around gun?
Mines a Fleming HK94 to MP5 conversion. They were once reasonable, this one was $800, $450 for the 94, $350 for the conversion.
Its got a few tens of thousands of rounds through it over the years and in all that time, the only thing that ever broke was a roller retainer clip. The gun was still running with it broken, I only noticed it when I was cleaning.