Board Thread:Monster Discussions/@comment-5402590-20140214221352/@comment-24572700-20140225205953

I'd go with the Heisei incarnation of everyone's favourite Godzillabot, without a doubt; since no other foe's really come as close to killing Godzilla as Heisei-era Mechagodzilla did (read: destroying his second brain). Showa MG came close (somewhat), but he had the smackdown layed down on him quite easily (twice, even!), and got severely downgraded in his second outing. Kiryu didn't come close to killing Godzilla, so he's obviously not higher than the other two. SpaceG and Destoroyah didn't really demonstrate power beyond what Heisei Mechagodzilla has as far as I can tell, so I can't see them being the most powerful monsters. Besides, neither of them have managed to get as far as MG did in doing away with Godzilla (though Destoroyah's case is understandable, what with his weakness to extremes in temperature and the fact that he was facing a living furnace of a Godzilla, though SG has no excuse besides Godzilla's plot-armor). Not sure who would win in a battle between Heisei Mechagodzilla and Keiser Ghidorah, though...

Of course, I'm not sure if MG counts as a Godzilla or not, though, so I guess Showa Ghidorah would be my other pick should Mechagodzilla not be viable.