No, it's better than that. A theremin is an actual instrument that you have to physically play, and if you want to make actual music it takes real dedication and practice. Plus you'd have to actually learn or write some piece to play. EZDrummer will do all of that for you. You can play it, and/or write for it, but you don't have to.
Edit - err...maybe I got that backwards. You'd have to play the violin too, and you'd have to program the drum machines, so EZDrummer is still better.
My original point was that there really is no comparison if you're looking for natural sounding drums, but not everybody always wants and needs that.