MC is not god. He is the epitome of human potential for ranged warfare. That said, I think Predator would win. MC needs a clear enemy and he is involved in OPEN WARFARE.
Let me re-iterate. OPEN WARFARE. Not assassination tactics. If a Predator was not combating MC in open combat and got the opening shot, dead MC. If it's open combat MC wins, simply because that is what he is bred and trained for.
Again, MC is not trained for anything but open warfare. He is no assassin, he is no infiltrator, he is no tactical genius, just the best possible soldier. And a Predator is not a soldier, will not engage in open warfare unless nessecary, and will attempt to kill in one shot, without being noticed at all. The only real advantage MC has is his motion radar, however, a Predator could pick him off with his uber shoulder cannon if he stays still.
Bottom line: MC wins in open combat, but in ANY other form he loses.