Looking for advice on a new optic for my normal patrol rifle. It's a Smith and Wesson M&P 15 T, with the extended quad rail, free floating barrel, and Troy BUIS sights both front and rear. I've had it decked out with all the Magpul stuff and have been running a Trijicon Tripower (good sight, but I want some magnification for more precision shots. I'm looking at either a Trijicon ACOG (either the TA33R-8 in 3X or the 4X TA31CH), or the Leupold Mark 4 1.5-5, and I'm considering the Nightforce compact 1-4. I want something that I can do decent CQB stuff with, but I want great accuracy - MOA at 100 - with a 16 inch barrel. Any advice from anyone who has experience with using these sights on an AR platform would be appreciated.