Predator would win, for a few reasons:
1. they pack weapons to hurt the prey, which
in this case would be terminators, therefore they
would pack something that they could kill them with.
2. hard to shoot something you can't see and yes,
this goes beyond human visibility, so no heat, non of
that crap that terminator uses would help.
3. terminator may not feel pain and that blah blah,
but this also makes it very confined in what it does
in certain situations, no adaptability skills=dead
terminator.
4. Predators are pissed off cos Arnie killed one of them
in the first movie, well, it's payback time you tincan
Also I believe that shoulder cannon is actually
a blasma cannon, not EMP, I believe I read it
somewhere, but can't find it now.
And I agree with D_J, OP would have them for
breakfast and then he would eat the aliens too