rhino is a nurbs modeler that is true but its whole purpose is to design perfect solid watertight models. nurbs are just the type of lines you build your model with. its industrial design software designed for making models that are going to be produced so its function is making solid watertight models. while you can produce surfaces as well, it is a solid modeler. if you end up with a model that is not watertight then that comes down to a sloppy workflow. rhino is easy to learn, powerful and absolutely perfect for producing model for 3d printing, injection molding or inc milling, etc. if your looking for sculpting type models then its not for you. rhino is very heavily used in jewelry, toy, marine, furniture, architecture and your average consumer products. imo rhino is one of the best tools out there for producing models for 3d printing. if you goto infiniteskills.com they have complete video courses. beginner and advanced. they are very well done and will have you up and running with it in a day or two.