I have the exact same motors. They seem fine for what I've done with the machine so far. I havn't seen the full potential yet as my drivers are crap...Currently building some new ones. You can see my machine here:
http://www.terry-is.f2s.com/
There's not much info on the site about the machine yet, as I'm still working on the site. Lots more picures of the CNC to add. (one day).
You might find some of the pics usefull.
Regards Terry.....