new build opinions required

[JAZZCNC]

No you miss understand. Mach is only limited and prone to crashing when using the Parallel port at high Khz ratings.
The Parallel port and it's driver are the problem when using high Khz and struggle above 60Khz.

Motion control cards free Mach of these problems and it's Now the job of the Hardware on the Motion control card to generate the pulses NOT Mach3.
Mach3 just passes the trajectory Data to the Motion control which Buffers it in memory then generates the pulses needed, which it can do at very high pulse rates.

The main differance between Mach3 and Linux Cnc is that Mach3 and it's Motion control cards have to buffer information and Linux works in real time.
Can't speak for Linux has I don't use it but I can for MAch3 and it's motion control cards and trust me it's not hype. They do exactly what they say and generate very clean high quality pulses very fast.!!. . . . . If they didn't there would be lots of very very unhappy people who are now daily running industrial machines for there living which have been converted to Mach and using high count Servo's with encoders.!!

Also not sure what your on about regards Bob and Servo drives.? . . . . Bob does nothing more than distribute signals and servo drive does nothing but receive signals. Again I think you confused here.??