Gotta agree with those asking about mods.
Factory Glocks, for instance, have a well-earned reputation for reliability, but all bets are off once they're modified, especially with aftermarket parts.
Also, as you know, most load their own ammo, so the quality of the reloads is all over the place. And on top of that, some insist on using loads that flirt with (or maybe even disregard altogether
) the lower Power Factor cutoff.
I'd look at more than just the name on the pistol, then. Ask about their load and what mods they did as well.