That is a good question. What little I have read about them is less criticism and more folks trying to figure out the point of this model. Within the S&W line up Sigma's a plenty are still around and the M&P is a big success at a reasonable price so I think would be buyers are a bit confused. Marketing and public perception is a tricky and important aspect especially in a competitive market segment this would be targeted at. Best guess it is a tweener between the Sigma and the M&P which doesn't make it a bad or good gun just odd they would offer it. If the Sigma is going away that would explain it.
As to the quality and merits of the gun itself, like you, I have no idea yet. We have some M&P guru's here so maybe they will chime in with a more intelligent and knowing opinion than mine.