Futureman's Drumitar is not only especially designed for his tastes, but its designed to be a replacement for a drum set, though ever since Drumitar v. 1 he's been using acoustic cymbals when needed. He now also uses acoustic drums when needed as well. The Zen Drum, as far as I can tell, was never designed to be a replacement for a drum set. It's sorta like its own thing. From what I've seen in videos, it's best for some handdrum style drumming, putting random effects on the pads, and doing some unique things. But you'll have a bitch of a time doing any kind of set drumming with it.
Personally, I would totally get a Zen Drum were I able to afford it. But since I can't, what I want to do is build a drumitar designed for me and what I want, but I have nowhere near the knowledge needed. I planned on asking this board if anybody could help me from afar
In the long run, it would be far more expensive than a Zen Drum I'm sure, but I'd only be building it piece by piece.