I have the Playstation version. Extremely fun little fighter, both PS and N64 versions have unlockable characters. Pretty clever reuses of in game models, too. PS version has Ravage and Botcon Tigatron from Cheetor, while Transmetal II BA is heavily reworked from Tarantulas. And she's very convencing, too.
Megatron is very challenging to beat, unless you use Rattrap, then he's a cinch. In fact, Rattrap is pretty god-like in this game. It's hard to lose with him.