IMHO:

Stay away from the EM-1 and EM-X. They're limited - the sequencer is nice, but the sounds are static; you can't really do as much with them as the ESX or the ER-1/EA-1 combos. They are really neat, especially if you have no other gear, but if you've already got a studio, or really know your way around software, the "M" boxes get real old, real quick.