Poll
88%
13%
Ultron would win cause he has a matter manipulator or whatever its called ALL I KNOW IS THAT HE HAS ONE GOT IT? anyway what that means is that its a weapon that can undoe the very fabric of a material even adamantium (witch Ultron is made of) and it would most certainly be able to undoe metallo's metal exo skeloton witch is supposed to also be indisctructable.
Ultron possesses a molecular rearranger witch can undo metals as strong as admantium and whatever metallos is made up of all metallo has is a kriptonight ray witch i dought will bother Ultron and he is not as smart and he is part human so Ultron could use his molecular rearranger on him or his mind countroll abilities or just take away his power source witch is kryptonite.