air spindle vs electric
 

I tried searching and found no information. I was wondering what the pros and cons of going with an air spindle as opposed to an electric motor. Thanks much.

AFAIK, in general, properly treated compressed air, i.e. filtered, de-watered & lubricated, will supply necessary lubrication to the running parts, it also does a great job at removing heat. No carbon to replace, don't need fancy electronics for speed control, and for any reason when the spindle get jammed, there isn't any wires to burn.
BUT they tend to have less torque at low speed. unlike electric motor & hydraulic motors.
That is why pneumatic drills usually comes in very high speed to make up for the poor torque characteristics...
Also pneumatic drills are noisy...

An air spindle's speed is very unpredictable and uncontrollable. The speed drops off with increase in load. The spindle can stall without any way of detecting it. It is okay for hand tools where the operator can hear the speed and adjust the load by changing hand pressure