RidgeTop, Xenomorphine, myself and one of my buddies had a wack at this yesterday. It was difficult! When 2 of us went down, it was just difficult to recover. Guess we need to actually level up before trying the bonus mission!
I dug it, though. The Predator is rock solid but it does feel a little like artificial difficulty and like the Predator is "cheating" when it suddenly disappears, not cloaks, just disappears, to move around the map.