I have been testing out Sculptis the last few days, and I have to say I'm really impressed with what you can do in the program, considering that it's free. It's also extremely easy to learn the interface, which imo is much better than both Mudbox and Z-brush. I wish it had better painting tools though, that would make it the ultimate 3D sketch program. But seriously, I shouldn't complain. it's a brilliant little program (and I say it again, it's FREE).