Regardless of who might actually win I vote for the Alien. Because he relies purely on instinct and his body. Whereas the Predator has gone the way of the human and come to rely on technology to do all the work. If you rip all that gear off a Predator, it wouldn't stand a chance. Even with it's gear, I think the Alien could still possibly win.
Let's hope the movie doesn't disappoint me
As long as we're on the topic of these battles between two seemingly equal opponents, can someone tell me who won the battle in Freddy vs. Jason?