The question is what do you want to accomplish, and how fast. Speed costs, patience costs less. People have a tendency to look at all three axis the same and they are not. A moving gantry design like a JGRO needs on the X axis are different than it needs on the Y or Z. In all honesty, the a3977 on a JGRO X wouldn't be my recommendation. A high 200ozin stepper is enough power but if you want X rapids to be snappy you need a higher voltage driver on the X. The A3977 is perfect for the Z, OK on a Y as long as the correct motor is used. Works on the X, but it is methodical.