Roughly six billion Mon-Els versus Superman Prime?
Uhhhhh....
Even if you go with the "not experienced with their powers shtick"... I mean, who would win in a fight, Bruce Lee, or SIX BILLION dudes?
Plus, a lot would adapt quickly to their powers. And some would have things like martial arts training. Superboy Prime just punches and wins because nearly everyone is weaker than him.
He was originally beaten by two Supermen, remember?