Most likely mega
I love the Mega's versatility but always seem to get caught out staying in prankster too long and get status'ed. Magic bounce is a lovely ability but you do miss your prankster speed and leftovers restore then, works well with trick room though.
What moveset are you going for? For my mega version I go with Snarl, calm mind, recover and willo-wisp as I find calm mind is better for building up his attack power for after hes gone mega. Non mega version I have taunt instead.