I had this question myself, as I purchased a WW SRC. There is a semi-famous youtube channel - Stermgewehre - that did a review on the MPC and the CDI. He had great things to say. He also did an AR-15 reliability demonstration using a Colt. I asked him on his Facebook page to do one with a Windham, and asked what is different between a Colt and a WW.
According to him, the only real differences are in the barrel twist and the buffer tube. (WW is a 1/9" and commercial buffer tube).
http://www.youtube.com/watch?v=0PVEitTfxm0