Too bad people are scared and bought up all the rifles. Here in Alaska everywhere is sold out of semi-auto rifles that are in any way military-ish, and so the only shops that have them are mom and pops shops and they are EXPENSIVE. I got my Colt for 1,100 with 3,000 rounds of ammo in 2009!!!
Regardless the M&P is a solid rifle. Now adays most ARs are pretty solid and don't differ much from one another as far as what you feel and see when shooting. There's some brands/modles to watch out for but for the most part if you can find an M&P for under $1K right now you're doing alright, but as someone else mentioned I'd wait a few months at least so all this hysteria settles down a bit so that prices can go down too. I suspect you'll be seeing a lot of people who stocked up on rifles thinking they'd explode in price can't get rid of them.