I have heard great stuff about Gecko drives. I also know that NEMA 34 are better than NEMA 23 motors. The problem is that I need to get this thing up and running quickly and the closest thing I can find to a turnkey kit uses Nema 23 motors and a Xylotex driver board.
I usually use a 34 frame stepper, more bang for the buck, in my experience, but you may not be able to fit that on your machine. The only drives I have used that have been absolutely flawless have been the Geckodrives. Top notch product and top notch support, Mariss is an example of how to run a small business (and he's a pilot too, always a plus in my book)