There is something new this year in the "demo" version. It is now called the Mastercam X4 Demo/Home Learning Edition.
This is different than the old demo versions because it is fully functional (except post processing) and also lets you save your files. It is not licensed for industrial use but you may use it as a learning tool as you desire. The saved files are *.emcx which can only be opened in the educational/demo versions or by a dealer hasp. This means anything you create with the Demo/HLE version will not be usable with an industrial hasp.
I do not believe that you can download the Mastercam X4 Demo/HLE but I am quite certain that your nearest reseller would be happy to hook you up with a copy.
So it's not quite a "hobby version" because you can't post an .nc file but this version would be extremely helpful if you want to learn Mastercam.
Hope this helps.