Comparing motion controllers...

[JAZZCNC]

If you are using steppers and don't need slaved axis or Backlash compensation then the IP-M is better option. Here's why.

The Cslabs controllers use 24V I/O which is very noise immune but more importantly they remove BOB from the equation which is weak area on any machine. This should not be under estimated because BOB's are big cause of trouble so any chance to remove is worth paying extra for.

Then you have built in spindle speed controller. Also another important area often over looked is the Software and support. Cslabs make excellent reliable software and support is great. This isn't the case with Warp9.
Quality of the unit has whole is excellent very neat and to industrial standard. The ESS by comparison feels weak.

Now to answer the questions.
#1 Homing on Index means if using servos with encoders you can use the Index pulse of the encoder to home more accurately than switches. It also allows much faster homing because can rapid at full speed towards the home position at which point you trigger a switch. This then slows the machine to homing speed then homes to the encoder Index pulse.

#2 Backlash is something to be avoided and best done by removing mechanicly not thru software. At best BL comp is fudge and not very affective. To me it has no value and wouldn't use it if did have it. I'd remove the BL mechanicly by others means or new screws etc.

#3 Spindle speed control is combination of hardware and Mach3. The IP-M provides Spindle speed control so it's no problem. The ESS does not and will need spindle speed controller or BOB with one built into it.

I've used just about most Controllers and NONE come close to Cslabs in quality and performance. If using the ESS then I'd only use one with high quality BOB like those from PMDX and if needing Spindle speed you'd also need there board for this. The combination of all 3 costs far more than the IP-M.