it depends on what other gear you have. if this is the first peice of equipment, i'd have to suggest the 303 as it has both the drums as well as plenty of bass and lead sounds. the ER has only half of that, you'd need the EA to do the other half. but if you're looking for techno oriented stuff, i'd save up and get the jx 305, it has a keyboard! whatever you do, don't buy anything for the preset patterns, buy a bunch of CDs instead.