I'll probably catch a lot of flack for this, but I actually feared Ground Resonance in the few fully-articulated choppers I've flown more than Mast Bumping in the 22.
I'm guessing its because I know how to avoid Mast Bumping and exactly what to do if I ever encounter low-g. Where as Ground Resonance seems to come out of nowhere (so I don't know how to avoid it) and I'm not 100% sure of how to get out of it?