I personally take interest in the predator, his unique style and ability to stalk even the most alert targets without notice and taking them out with his arsenal of unique weapons is just unbelievable. Plus i believe in one of the AVP comics it denotes that Predators Blood is the Base to Aliens Acid making it Non lethal underneath the skin of a predator.
On a side note the original predator movie has the best quote of any of the movies from these 2 phenoms,
"I Ain't Got Time To Bleed" - Jesse Ventura.