Pointless question, but Batman. He would know how to stay ahead of the terminator and how to beat it. The terminator is just a machine that blindly follows the directives it is given for the mission.
I would say it would be easy for Batman to win. Unless you mean the liquid terminator. Because Batman would have easy access to explosives needed to blow the 'Arnold' terminator to hell.
I have figured out Super man's secret identity. Its that Clark Kent guy. I mean seriously, picture him without the glasses.
On a related note, anyone else find Batman v. Superman pretty dumb? I mean, Superman is practically a god. Batman is just a dude...
Batman it a tactician, and would know all the weaknesses of every superhero. Superman is vulnerable to Kryptonite and Batman knows this. Batman would have kryptonite laced armor and weapons making Superman human in essence.
In a fight, obviously the Terminator. But if Batman were to take on the mission of destroying the terminator, then he would be successful; not because of fighting ability, but because he has billions of dollars to spend; he would figure out a way to destroy the terminator while keeping distance.
On the other hand, if a terminator were to take on the mission of destroying Batman, then he would also succeed.