The main advantage to using the grooves milled in the top of the receiver is it allows you to mount your scope as low as possible, thus contributing to a positive cheek weld. I used Warne rings, and they clamp on with a bulldog grip, they look good, are lightweight, and don't have anything sticking out to catch on stuff. If you plan to wear your barrel out and rebarrel right away, you can always get the quick-release option for easy return to zero. Warne's are great rings. I understand Talley's are also topnotch.
I can't imagine a rail on a 6 1/2 # rifle, but all the Chris Kyle wannabes seem to love those things. Pretty useful I guess if you want to shoot targets the size of a Volkswagen at 1200 yds.
forepaw