I've built four Microstep drivers from embeddedtronics.com and i'd recommend them even if it was a first time project.
I bought thier bare boards as it was cheaper than ordering or even making them. Nice quality. I got free samples for the pic's from Microchip.com and samples for the LMD18245 from national.com. National sent a bag full..
I had some problems programming the pic's until I built a decent programmer. nothing to do with the code, I did have to change the code available at the time to suit the 628's I used.
There are limitations which are the same with any driver using the LMD, 3a and ~40v might be less power than you'd like, the LMD18245 can be a bit delicate and I'd suggest not using more than 36-40vdc for the motors, never disconnect while powered up. I tried higher voltages and blew a chip, before it went I didn't get any measurable gains over 38v. I'd heatsink the LMD's too. The boards are small and so i'd suggest you mount the boards and the heatsinks seperately.