I am an old Master5 user (three years or so), on a home-built plasma cutting table, like a big plotter.  It is 2 axis only, I run the vertical axis motor manually.  
Question:  Besides operating on a Windoze XP platform, is there any advantage to me to upgrade to one of the Mach packages?  One thing I would like is to have cutter compensation built-in, instead of having to pre-process for compensation.  Does MachX do this?  What other neat stuff am I missing using the old Master5?  Which version of Mach do I want to start with?
Thanks for any hints, suggestions, opinions.