Hello gumby:
That's quite a laundry list on Ajax. I was under the impression the Centroid/Ajax was pretty well debugged since they have been around quite a long time. However, they are a proprietary system, and the first order of business is keep their software locked up tight, and charge what the traffic will stand. That is pretty standard industry/corporate policy.
Regarding your questions about the Vital System, dspMC/IP controller, I have nothing but good things to say. The company is on top of any problems, and work with users to make things work. They are improving the software/firmware and make their updates available via the internet. There are no "special codes" to get things working.
There is no auto-tune, but the PID tuning is now done in a plug-in screen set with tabs for each axis, which is accessed from within the Mach3 program. No shut-down, restart. The tuning has a big graphic screen which shows visually the acceleration/decel curve vs time. You can keep changing numbers, run an axis back and forth in real time, and play with settings until you get a best fit/feel/sound from the axis, then save your settings to the controller, and to the .XML file. There are more advanced settings on the tuning graphic that I have not used yet. My machine seems to really run fine and smooth with the basic settings that I found by experimentation, and the manual suggestions.
In my situation, the installation is a retrofit for an orphaned system that is now out of business. My motors are DC brushed, approx .7 KW, 100v Westamp amps, and the motors run smoother and faster now, than the original controller.
The controller has analog spindle control, and (3)MPG inputs directly to the I/O board. The higher end dspMC/IP controller has analog I/O, which is a nice option. I do not have that controller.
Quadrature encoder inputs, plus index via Z channel homing. All working a OK.
There are two types of I/O boards. the 7535 is buffered and optoisolated, 12-30v dc I/O, and each board has 8 outputs, and 16 inputs. Using two boards in the J4,J5 position gives a total of 16 outputs, and 32 inputs. The corresponding Mach3 pin numbers are in a correspondence table, keeping everything pretty simple.
That pretty much sums up my experiences.
There are some very experienced, professional machine builders/users on this forum, who could give more detail regarding PID tuning.
John