Unipolar or Bipolar?

Hi CCED group gentlemen,

I am modifying my Grizzly mini mill to CNC, I have bought Nema 32
Vexta PH-296-2B steppers, with 5 volts, 1.25 Amp, 6 wires.

After read several messages in this group I continue with the
following doubt:

Since that steppers are Unipolar (6 wires), I don't know what
controller is better for good speed performance, Bipolar Chopper
(like 297/298), Bipolar Microstepping (like Xilotex) or Unipolar
Microstepping (like Linistepper).

Thanks,

German