I use it, Im not a pro at it, but I've used it as my main 3rd for awhile nowz. The problem with it is you can only make 10 brushes (just single objects in the creator) in every file. Once you get to understand it, it really ties ur hands together in creating. The only way around it is to copy and paste brushes, then edit them, or somehow perfectly line them up in the editor.
There is a registration key that registers it and let's you put as many brushes as you want, and then you can make amazing objects. If you've ever heard of crazy coaster, and seen his rides, Aeris, Xibalba, they are spectacular and made with the registered OC.
Once i get on my computer in a few hours I can tell you more about the actual program. ;)