These bastard machines tend to give you the worst of both worlds. You get a flimsy, underpowered CNC router that can't handle much more than foam, and a slow clunky printer. Dremel tools don't make good CNC spindles; the plastic housings deform after about a half-hour of use and then they die. NEMA 17 motors are fine for printing, but too weak for more than the lightest carving work. I'd say start with a printer, and once you're confident of your DIY skills, attempt a dedicated CNC machine that's as rigid as you can make it, with a decent spindle.

Andrew Werby
computersculpture.com