Seriously ... I just purchased my first gun ( m&p 40 pro ) less than 2 months ago. I've put a little over 1000 rounds through it as of this weekend. The only problem i've had are feeding (magazine) issues. These problems arent from the mags that came with the gun but with a couple i've purchased online. From what i can tell you cant go wrong with any of the three, it's a Chevy VS Ford type of situation.
IMO if you get an M&P 9mm or 40 cal, go with the Pro series or you will want to put in an apex kit for easier trigger pull.