I found linuxcnc quicker and easier to set up than Mach3. I also find it simpler and more intuitive to use. Linuxcnc has advanced a lot in usability over time.
To do some fancy things can require some simple editing of text files, but i find it more reliable and with greater control of how i want it to work.
Setup for 3 axis with limit switches, home switch, spindle sensor and various other options is all handled by an easy gui wizard. The general install is a dead easy livecd then install.
I'd try it for a couple of hours before shelling out for Mach3.
Probably the biggest problem with linuxcnc is that there is less info available targets at the new user. A lot of what is around is hard to understand at first.
7xCNC.com - CNC info for the minilathe (7x10, 7x12, 7x14, 7x16)