I'ma go with the obvious winner, Terminator, just going by what they've done in their various film appearances.
Both are kind of ludicrous when you think about the way they were presented, but that's probably because they had to give humans a chance against them, which realistically with that kind of tech would be pretty unlikely. With more realism added, I think things would get much much much worse for the Predator or any human/flesh/blood type enemy.
Think about this, a modest computer today can basically murder anyone on the planet twice over with FPS AI set to max. Not that it's all that smart, but it can be set to aimbot like a mofo to the point where as soon as you're .000000000000001% in range of their weapon, you have an insta-head shot to your brain bucket. Reality would be a lot more like this when facing an AI-based robotic gun-wielding opponent. A processor or series of processors constantly anazlying environmental details and movements hundreds of millions of times per second, and with the reaction times to match? GTFO.
Of course, this more realistic interpretation of what dealing with that kind of enemy would be like would make for a boring 10 second film. Skynet goes active, makes terminators, they killed everyone, the end.