Well ... I've been Mach for years, since it was Master 5 ... over several different computers and CNC's. The main problem is that occasionally Windows background tasks cause 'skipped' steps (not missed output steps). I've hooked a scope and frequency counter up in a count mode ... Mach never misses steps, but occasionally enough of a delay in the pulse train at the wrong time will cause a motor to skip. This can be overcome by running your CNC slower such that the acceleration component isn't critical. Using the ncPOD gave me *much* smoother motion. No clunks or bangs (I use THK KR slides, so I hear anything that isn't perfect) when the hard drive light occasionally fires up from some other background task (yes, I've disabled *everything* possible). I thought I was home free with the ncPOD. However, in the middle of a long program I've already once experienced a problem with Mach3 and ncPOD. I believe Mach is sending the G-codes one at a time. While there is supposed to be some buffering on the device (per the SDK notes from OEMTECH), I've witnessed a long enough delay to cause the same time type of pulse train delay between commands while an axis is at full speed (in this case, G04's transitioning from one arc to the other). I've loaded one of my long programs into the SD card on the ncPOD using OEMTECH's VB panel. Heavenly -- it works perfect, smooth motion from start to finish ... never a hitch. However, OEMTECH's VB panel is rudimentary. It would like to use all of the features I've gotten spoiled on in Mach with the ability to run autonomously from the SD card.