I tried one at NAMM last year. The action was nothing to write home about: standard synth “plasticky” action. Not what I’d expect from a $600 keyboard. I still think that the best solution would be to get a GREAT keyboard controller (like the Akai MPK88, which you can find online for as little as $600*) and then either CMC modules or a tablet controller like IC Pro. Or a combination of both.
(*) http://www.bhphotovideo.com/bnh/controller/home?O=&sku=598795&Q=&is=REG&A=details