I have 2 M&P AR15 OR's and they are great rifles and would recommend them to anyone.
That said the Core 15 rifles are also a great deal on a full Mil-spec AR with 1 in 7 twist to shoot pretty much any bullet weight available to the 5.56.
Bud's has them for $750.
http://www.budsgunshop.com/catalog/p...O+16%22+30%2B1