I think the Sig Romeo 5 is the best red dot on the market for $150 or less. It comes with every feature you could want and is tanky enough to take a beating and continue functioning. 50,000 hour maximum battery life, motac, clear glass, 2 moa dot, and standard mount compatibility with just about every aftermarket red dot mount on the market. I have put this on several different rifles, everything from shorty ARs in 5.56 and 7.62x39 to AR10s and it has held up excellently with no shift in zero even after dropping it twice from shoulder height. Most of the time that I have been running it I have put it on a UTG .500" 13-slot riser and it pairs very well making close range and out to 300 yards fast and intuitive. It has some competition from Vortex and Holosun but I think this one is the best overall dot for the money.