I'm still learning the program but have used Alias for the prior eight years and that helps with the transition. The major difference is that there is limited history built into Rhino which I guess accounts for the more affordable price but changes the way one constructs objects; you need to save often.
Overall Rhino has plenty of capability and the interface is pretty much straightforward if you're at all familiar with 3D modeling programs. The Help does include short videos that make it easier to understand vs. reading just text.
Novedge delivered the product very quickly and had a very good price.