For Mach4: The Ethernet smoothstepper, ESS is the way to go.
Then CNC4PC have some decent breakout boards. Or the UCSB from cncdrive. You only need a fast one for the axis drives and any encoders, the rest don't matter as much they'll end up being mostly switching. This will help with costs.
If keeping costs down but want good standard stepper setup, this will do nicely:
Nema24 stepper: https://www.omc-stepperonline.com/p-...s-24hp39-5004s
Stepper driver: https://www.omc-stepperonline.com/di...4-motor-dm860t
Running these on 80v gives awesome velocity and acceleration. The steppers are about the best there are in the size and price range and great driven at the higher voltage.

If your thinking of using AC servos then get the ones from Delta.

I wouldn't bother with Gecko stuff.