well for adventure time.., i like how the story are going , i mean they still have soo manny mystery in the story (like how, can jake the dog talk, why is finn live in world of ooo, who is finn dad, etc.) and if you search in youtube "Adventure time Theory" you can found sooo many theory that explain all of that complexity , the world of ooo is HUGE
and for the regular show... its just a show about 2 animal (mordecai&rigby) make a little problem , then become a HUGE problem
just for an example :cant be the judge on a pie contest, accidentaly release a monster pie
and their world is pretty wild too, i mean.. what creature is muscleman? why there are a high-five ghost? bring an army just to take a van? chasing some rusty robot just for fuzzydice? margareth father is a human, but margareth mother is a bird... WTF? i didn't say regular show is bad , their wild world make this show more than regular
in fact i like both, but my vote goes to Adventure Time!