After about 15,000 rounds fired, the slide stop broke off on my M&P40 Pro. Called S&W customer service. They emailed a shipping document and returned it fixed in under 3 weeks. No charge to me for anything and they included a 10 round mag for free.

Also later called to buy spare recoil and striker springs. Customer service just mailed them to me at no cost.

YMMV, but I'm a happy shooter.