I was just contemplating the same three budget ARs. My Ruger is on the way to my FFL holder. I think any of them would have served me quite well. I would guess that most people who want a black rifle want it just because. That was my excuse. Ruger has a forward assist, dust cover and a flip up rear sight standard as does the S&W. I opted for the Ruger because I am a bit of a Ruger fan. Academy Sports has the DPMS for $499 right now, so that price is very attractive. Just buy one of the thee and live happily ever after.
