If you look online, the M&P can be had for about $450. The above post I think was a typo, lol.
From what I've read on various forums, the Ruger has had some issues with trigger failing to reset and some barrel peening and the M&P has had issues with broken slide releases. Either way, both are manufactured by great Ameican companies with excellent Customer Service. So if there were any issues with either gun that haven't been ironed out, you'd be taken care of promptly.
The Ruger comes standard with an external safety and mag disconnect saftey whereas with the M&P, you can have it with any assortment of configurations with or without each.
The SR series does have a better trigger reset than the M&P. It's very Glock-like. However, this can be fixed with aftermarket parts from APEX tactical. The trigger is usually the biggest complaint about the M&P. The SR9c/40c have great reps for triggers. You can further customize the SR trigger but the only aftermarket trigger parts that I'm aware of are from Ghost, Inc. and require a gunsmith to install.
Bottom line.....both are great American guns built to last. Aftermarket support for the M&P is a little ahead of the SR series for now. To my knowledge there are no 9mm conversion barrels yet for the SR40/40c. Rent or borrow and shoot both if possible and pick what fits you best.
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government." - Thomas Jefferson