I want to get a nice long range scope for my M1A, I have narrowed it down to the Millett LRS 6-24, the Vortex Viper 6-20, and the Nikon monarch 5-20 or 6-24. Anyone have good or bad experience with these? I am not looking for my brothers uncles cousin read on a bathroom wall...... kind of stuff. I want to know if you have one, likes and dislikes.