I run GRBL and UniGcodeSender with A4988 drivers. They work well together. But the only drawback of running GRBL is the missing some of the better gcodes. Like tool offset for one that makes me have to draw the offsets and does make it harder to get a part correct the first time. As for as Arduino, GRBL, and the rest of the hardware you can't beat it for price, dependabilty, and ease of installing. A run around the net for wiring dirgams and voltages for each type of setup is a safer way to build you cnc. I spent and still do spend hours surfing info on different ways to wire my 3 cnc's.