The fight takes place on a Braniac ship. Both have 24 hours prep. Can Brainiac take down Ultron? Or will Ultron outsmart Brainiac?
@Maruke: Can you specify which version of Brainiac? We actually know very few specific about the DCnU "collector" Brainiac.
However, if we're indeed using the current versions of both characters I'm going to say Brainiac is more intelligent and has better tech. Ultron however I'll give the the upper hand in pure physicality to since the most recent Brainiac doesn't really have any showings.
In the end though, I think Brainiac just BFRs Ultron via dwarf star lens.