After a great deal of debate, trial, and research, we loaded a computer with FreeDOS and TurboCNC. To sum up the argument, windows based controllers, in my experience, suffer from an endless chain of issues associated with the use of hardware abstraction layers to provide "security." Linux works well, and offers EMC2 (free), but after a few arguments between myself and the system I decided this was a good place for pure simplicity.
TurboCNC reads control code (G-Code), interprets and outputs directly to the controller. Simple, straightforward, constistant, and free to mess around with. Donate the guy some money once you decide TurboCNC is awesome. Same goes for FreeDOS. These guys put a lot of work into their software for our benefit, and should be rewarded.
It took less than 5 minutes to get TurboCNC moving the machine, where we ran a few test files just to see everything work together. Messing around we were able to achieve some pretty good speeds (up to about 140 IPM, not bad for a heavy machine under powering its motors). Also, at 75 IPM the machine feels totally unstoppable. You can push and pull with all your might and it just keeps tracking along regardless. Also, there is no discernible play or flex in any dimension. When the motors are held constant it feels like everything is just welded in place. I do believe this thing is going to work: