I have used Rhino almost since the beginning as I preferred its modeling to AutoCad. Then I dropped AutoCad almost entirely when Rhino's 2d drafting and dimensioning were sufficiently developed.

Now I do most of my model making in MoI and use Rhino for 2d stuff and dimensioning as well as the program to work with the rendering program I use (Flamingo).

MoI is very easy to use and a great modeling tool.

my 2 cents.

eric