I use 2. one i got off ebay. it's a liksang smartjoy. The other is a generic joybox 3. both u can use for dance mats. which brings me to another topic. Dance mats. Some psx converters do this with dance mats---
Mat Press stepmania press/what ever ddr program
up up
down down
up-down down - or - down
It doesn't register the 2nd step. what happens? the decoder thinks you are a d-pad. that happens u get a cheapo one. the better ones register the up-downs and left rights.
hope that helps!