Robin2:
If the A4988 can supply the current required by the motor it will work just as well as the TB6600.The A4988 should work fine with motors that take less than about 1.3 to 1.5 amps. The TB6600 can provide up to 3 amps IIRC.
...R
With frequently used Nema 17 stepper motors which have 1.8 deg/step property, I think there will be no problem in using A4988 as you said. But if I decide to use VEXTA PK243A1-SG18-C4 Motor I need higher capacity of current.