Local department is shooting several firearms while they consider moving away from Glock 22 because of the accessory rail issues. From my understanding they are leaning towards the XD(m) as their choice, so I can't imagine it is giving them trouble (especially since the Smith M&P has a lower price).
If you have issues with the gun I would continue to send it back to Springfield (or see if they have an armorer locally they will endorse), and keep sending it back until it works or they offer you another pistol.
I can understand why this experience might sap your confidence in the piece. Good luck, let us know how it turns out.
I don't make jokes, I just watch the government and report the facts. -Will Rogers
An appeaser is one who feeds a crocodile, hoping it will eat him last. -Winston Churchill