Just my $.02: I just put a Redfield Revolution 2-7x33mm on my RRA LAR-8, using the Burris PEPR mount. Owned by Leupold, lifetime warranty, and made in USA. Good price too.
Not the typical choice for a an AR in .308, but it was a good comprimise between the amount of weight I wanted to put on, and desired magnification. This is a deer rifle for me, not a precision tactical weapon. So, I guess the amount of glass you put on it, depends on the intended purpose.