Just started with this a few weeks ago, only used Mastercam 8 at a previous job, and though the commands take a little getting used to, this software is a great value for me. The training DVD's help a lot and the functionality/price ratio is great, at least for my application on a 3-axis knee mill converted to Mach 3 running in my basement.
The simulation feature is one of my favorites, though it shows the weakness in the computer that I am running it on. That computer will be upgraded soon I hope.
Thanks to the Bobcad guys for a good product at a good price. Ten years ago my colleagues scoffed at it, so I never gave it much of a thought until it was time to spend my own money. For my $$ it's the one to have.