Just about the best - Trijicon ACOG 4x32mm Dual Illumination Scope and Red Dot Sight

Love this optic. The first one I purchased actually came with a couple small dents on the side, which was a disappointment. The exchange process was a bit of an effort due to some unusual circumstances but to make a long story short, the big takeaway was that OpticsPlanet made it right and came through with good customer service in the end.
The ACOG itself is excellent. The QD mount is rock-solid and a nice improvement over the standard ACOG thumbscrew mount for those who intend to mount flip-up sights as a back-up. The side-offset irons are a nice addition and I believe only available on this model. The RMR is the standard type1, always-on. It's an RMR so the glass is clear, reticle highly visible and construction robust. The main ACOG sight is standard 4x32 side but with a nice FDE color that's well-matched to popularly available accessories. Mine is installed on a custom 16" AR flat-top and it blends well to the black/FDE scheme.
The picture through the scope is amazing. Crystal clear, and exceptionally bright with no curve or blur around the edges. The cross-hair and range tick-marks are clearly etched and easy to read, with a small reminder of the intended caliber along the bottom edge of the sight picture. The tritium/FO illumination is excellent as well. The tritium is extremely effective in dark environments and the fiber optic gathers an significant light, despite being slightly shorter than standard dual-illumination ACOGs. It works well for the fine, cross-hair reticle.
I've had some nice optic, including Aimpoint, Eotech, Nikon, Trijicon long-scopes and this is about tops. It really is the complete package and I highly recommend to anyone looking for a versatile, ultra-durable high-performance optic.