I'd like to hear from folks who own the M&P with a thumb safety. Take a close look at the safety. Does it have an area where it appears that the plastic/synthetic piece was broken off after being made? Like a "bad spot"? I'm thinking about returning mine for a new safety even though it functions properly.
I just purchased the M&P 9 with the thumb safety. I love the gun, but I wish I had realized earlier that the safety wasn't metal.