We were just talking about this today at the field. Heli pilots do seem to become much better fixed wing pilots and learn much faster. The Cub will put you to sleep pretty fast. The Heli pilot we were talking with is also an outstanding fixed wing pilot and was flying his really SMALL Cub again today. In his hands it is a stunt plane. The two you offered as a choice is a huge distance apart and there are a lot of in between choices, the stick is just one of them.
How about asking someone to buddy box there plane with you before you buy your own. I have my Hots fun fly plane set up on a box and let people give it a try just to see the difference between it and there more sedate planes. My Hots is set up on the really stupid side with 3-D control throws and a YS engine twice the size called for. It's an eye opener for most people. The Beast?? Probably not but the same for the cub. It won't take you long at all to be flying with the best of the pilots, you know what the left thumb is for better then most and have great reactions.
Ask if anyone will take you up with a box before you buy. You will probably be able to solo in one day with a bit of help.