I still can't get used to being the predator. It seems my cloak ability is always broken.

The last game was kinda fun because 4 out of the 7 guys were marines. Even though that predator was a bit annoying.
If you stand really still as the predator it's almost impossible for a marine to spot you when cloaked, but when you start moving around you become much easier to spot as the motion tracker helps point the marine in the right direction and then they can see a slight shimmer of the cloaked predator.
I'm amazing as the Marine. I take the hunt to the hunters. They fall consistently to my barrage of bullets. I love it, and I very often place in first with high kill streaks. The marine is definitely not to be thought of as weak. They all play very strongly if you use them right.
Yeah, every species is powerful in the right hands. I think it's very well balanced.