The link below is a pretty good Forgotten Weapons summary of the automatic pistols and calibers which were available around the 1900 period. It provides a pretty balanced view of the relevance of the Mauser C96 in it's own time.
By all accounts the C96 is less favorable than more modern pistols by WWII time frame, but the Germans had to make use of what was available, and the Waffen SS in particular were saddled with a lot of non-standard stuff due to their different supply chain earlier in the war. If I were issued one, whether it was full-auto or not, I'd pretty much use it as a semi-auto pistol. It's not perfect, but fires an adequate cartridge and holds at least ten or more rounds. Reloads would be slower, at least for the stripper clip fed versions, but at least as fast or faster than most of the revolvers used by UK, USA and the Soviet Union. I think what's less clear from looking at the C96 (as opposed to shooting one) is that it's a big clunky gun which is awkward to fire with two hands and a little clumsy and front heavy with one hand.
Also, as Ian from Forgotten Weapons points out, when new, these pistols, which were basically hand-fitted using old world craftsmanship, were considered very functional and reliable. Nowadays, with many of them being over 100 years old, and in some cases heavily used and/or neglected, their reliability is more suspect.