Phil -
I am using the versi9on of Mach3 that is downloadable from the internet.
As far as I know, there is nothing disabled in the program itself, and it certainly all works fine on my set up (both lathe and mill)
The only thing I know that is limited is the number of lines of cade that can be used, and the downlaodable version is limited to 500 lines of code.
Lazy Cam and I suppose other add ons are limited
Jim