I'm a long time bolt gun guy that's pondering an AR due to today's low prices. It'll be for plinking and home / self defense. Prefer a finished gun, no desire to "build" one. I want it to be a carbine with open sights in the under $700 range. School me on the differences, advantages, disadvantages of all the brands (S&W, DPMS, Core, DelTon, Ruger, Windham...........). As of now, the S&W Sport at about $600 looks pretty good to me.