Searched around and couldn't find exactly the answer I was looking for...

I have a home built CNC router aprox 22" X 29" loosely based on OX components...have rebuilt the thing several times making improvements along the way...I designed and built a nice Z axis with linear rails and an acme screw, rebuilt the X gantry with linear rails also...still a belt drive machine, but I have VERY good repeatability with the belts (less than .0015") on all axis...anyhow, thinking about building a stronger machine like a minature version of one of the high end machines...will probably be 24" by 40" or so...

There are kits on EBAY complete with linear rails and ball screws and double nuts in the sizes I need, but I prefer the simple design of the frame and such using rack and pinion. A LOT of high end machines use rack and pinion. Just want the best setup in the size I want.

I would either build or buy a 4 to 1 drive system like CNCRP sells...so what I am looking for is opinions on this type of rack and pinion versus the chinese ball screws as far as accuracy and repeatability. I will be reusing my nema 23 motors. RIght now I cut wood around 50 ipm and have rapids of 160 or so, whcih is okay for the work I do,

Thanks
Leslie