During my run to 500K, I used an original controller. Instead of using my thumb I held the analog stick between my thumb and first two fingers like it was a tiny joystick. Seems to work much better that way.
Madcatz's arcade stick simply is not the answer if you're looking for a custom controller.....
your question is very valid and one I pondered over myself in an effort to get to the " next level " with my own scores
after much research I can tell u it is possible to use a Playstation controller,or,even bettter,a PC stylee analogue stick
u do have to buy an adaptor as well,at about £60
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