Orochimaru vs Pein

who would win in a battle ?

don't think that summoning Manda(snake king) will help in fighting pein. If it does help, jiraiya would have summoned Gamabunta(frog boss) which is equivalent to Manda in his battle against Pein. However, i would agree that Orochimaru is harder to crack than Jiraiya in terms of skill and Orochimaru has reincarnation jutsu. However, don't forget that Pein was just toying around with Jiraiya without even directly confront him in battle. Instead, he was just using bodies not of his own! There are still many things we do not know about Pein and I think he has more abilities to be shown in the coming battles. Remember what Jiraiya said, Nagato(Pein) mastered various elemental jutsus and this has not been shown in Naruto manga. Besides, i don't think Orochimaru knows any secret about the mysterious Pein and letting his guards down will be fatal

PEIN chibaku tensei will kill oro shinra tensei will fend off his reaincarnations and destroy manda like he did with gama and the others fighting naruto and shinra tensei to pull him to his 6 patyhs and preta path absorbs all his ninjutsu since or sucks at genjutsu

I'm Sure Pein would win, but Orochimaru would have a chance, He has many Jutsus that we never got to see, uncluding his Forbidden Jutsus that he stole from the Leaf Village that we never go to see