personally I think my boy Megatron's gonna win

MegaJ

Didn't Megatron kill an entire planet, while J was done in by a robo-raptor and before that an edgy grape?

Yep. He also killed possibly thousands of Autobots and ripped out a guy's voicebox, tore what was essentially a demigod in half, ripped Jazz in half if the first movie, and nearly destroyed earth multiple times (come to think of it, I severely overestimated J)

megatron. they have a rail-gun.

yeah, and we all know what happens when J and rail-guns mix

fr tho.