M.A.S.K. was badass. It was like Transformers meets GI Joe.
Those were the days of the good GI Joe action figures too. The ones with reliable metal joints.
The best playsets I remember: Ewok village, Ninja Turtle Sewer/ Tetradome, Gi Joe Rolling Thunder / Cobra Terrordrome / Aircraft carrier / Shuttle, Wayne Manor / Batcave (there's been tons of them now)
of the ones I owned, I had the most adventures with this:

Somehow I never got to play with this:


Looks like it could engage your imagination, but honestly it looks a little boring. Did anybody else have that one friend with a GI Joe room? But he never let you play with them without overseeing your every move? In fact he would realize the toy you pick up is the one he wants to play with most? EVERY TIME?