As far as feature set, you should probably look at this new chip as an upgrade to the A4988, with much higher microstepping and slightly higher current handling. If you’d like to experiment with ...

The stock USB-nSTEP focuser [Jerry] used required hard-to-find unipolar steppers, so he modded his USB-nSTEM to accept bipolars with a Pololu A4988 driver. Next up is [Jerry]’s very impressive ...