It was the duty gun of the German army for many years so, you gotta figure it has something going for it.
They are nice guns and, at the price the surplus guns were going for, an outstanding value. I've heard not to try and hot rod them, stay with standard pressure loads. I don't think they will come apart or anything, but wear will be accelerated. Look for one with the hex bolt through the frame, later mod to save wear an tear on the aluminum frame.
I have one, bought it when they were dirt cheap, sadly, haven't shot it yet.