>I think most of the OSX users would consider OSX itself to be the main benefit!

CORRECT

>But the overall main reason to do a port is to attract more brand new users who are not already using the existing software since it does not run on their operating system, rather than for existing users.

- Michael

About 60% of the beta users are current Rhino users on Windows. I expect most will want to switch. I don't think we'll attract many non-Rhino users until we have a real Mac OS X interface. Robert McNeel
http://www.architosh.com/news/2008-08/0814_sig_interv_rhino_osx.html