I did look into Mach3 when I found I had to replace the control system on my Conect lathe, but went for the CDE system based on cost and the difficulty in continued support for parallel ports on PCs. The serial port solution seemed more supportable and easier to add on newer PCs so I went that way. Also CDEs controller comes with a copy of EasiCNC whereas a proper copy of Mach3 is extra cost.

Having said the above I notice that there are some USB to parallel adapters appearing especially designed for Mach3 so that particular objection may become irrelevant.

David