The contest is over before it's even started... Predator wins... hands down, for the following reasons:
1. I said so...
2. The Predator has a great range of powerful weapons that could destroy the Terminator in a matter of seconds, he has the smart weapon aka the Disc (which locks on to a target that the Pred specifies, which could easily decapitate the Terminator, and thus rendering him pretty much useless... unless he gets a job as a talking toaster. The Wristblades and also CombiStick aka Spear, melee weapons, but with the great strength and skill of a Blooded Hunter (Yes I'm a geek who likes to read the AvP novels
) of a Predator could again make short work of the Terminator. Plasma Pistol & Shoulder Cannon, now I'm not exactly sure how resistant the Terminator's endoskeleton would be to a plasma ball, but Predator technology seems so much more advanced made up of materials (especially metals) not of this earth that are lighter and much stronger than anything from Earth materials (which the Terminator is made from), so I'd say that he could burn a hole right through the skull of the Terminator... melting the chip and desrtoying him.
3. Terminators seem to have one track minds, which is to terminate their subject no matter the cost, so it's like a walking tanks, runs in head first, where as Predators are stealthy hunters, who like to stalk their prey and take their time waiting for the right moment to strike, plus they have a cloak generator, which bends light, making them basically invisible. So I'm saying that the Predator could easily evade the Terminator and strike a fatal blow before the Terminator has a chance to realise why the hell his skull is being mounted on a trophy wall on a strange looking spaceship
CONCLUSION = Predators r t3h r0x0ring d00ds ... tbh
Or I could just be totally biased towards them