I am running a windows 7 laptop with new mach3 installed and a smooth stepper. Works great except for two items. One - never power off the smoothstepper with mach3 running - the communications popups are reminiscent of the old explorer days when your screen would fill with new instances from "those" sites. Only way to kill it is with task manager and it might take a few tries. I select all the popup instances as well as the Mach3 instance and kill them all in one shot. That works every time.
Second Item, which might not affect you unless it is a plasma application, is that a torch height controller cannot work with Mach3 and the smoothstepper. The THC control code is apparently in the parallel port driver which makes good sense because of the need for quick control. There are a couple of ways around that though one being a stand alone THC unit. Other than that, Mach3 and smoothstepper produce a really smooth running CNC.
My application is Plasma Cutting. I am running one of those innexpesive Wantai motor CNC kits on the new machine. I must say, I am impressed so far. My previous CNC Plasma set up cost me a few thousand and this one, A 12' by 4' is stronger, smoother, higher resolution and under $1,000 including Mach3 and the smoothstepper. $1,300 if I include the steel. Now, i am not putting a dollar amount on the time to build of course. These are works of passion. - Hmm, I remember a day long long ago when motorcycles, cars and girls held that spot. - CNC is better, it pays you back