Anyone using CNCdrive products?

[JAZZCNC]

That's what appeals to me more about the Linux cnc is that it seems to be much more like a purpose built cnc control (as in Fanuc, Heidenhain, etc) rather than a cnc programme running on windows. I'll have to explore further I think.

Not really it's still software based working on PC limitations.!!
Fanuc, heidenhain etc use Bespoke Hardware mixed with software to provide there High speed high quality pulses etc. So actually in reality the Mach3 and External motion control cards like Cslabs, Kflop etc are closer to Fanuc Heidenhain in this terms because they use Custom bespoke hardware and software combinations.
But Still there is one BIG difference with Mach3 and Ex Mo cards in it's still a Buffered system and not real time. Linux Cnc is real time and this does make a difference esp with servos and encoders. But I Still think you'll have a lack of Frequency issue because of the restriction of the Parallel port Architecture but I'm not sure what that limit is running Via Linux.?

Kflop is worth a serious look actually because think it can run on both linux cnc and mach but again it's not cheap.!! (and I may be wrong on running both.?)