US Optics scopes can be obtained with 44mm Objective, that's hardly any bigger than the 40mm you'll find on some of the Leupolds and smaller than the 50mm on some others.
Leupolds CS is some of the best. USO spotty.
So my breakdown:
Leupold - Best bang for the buck. Good quality optics and construction. Decent price. And with Premier Reticles Gen II Mildot, the best reticle (IMHO) available. Also, the reticle is available in front focal plane so you can range at any magnification. Mark 4 scopes are very sturdy.
Nightforce - Great optical quality. Better than Leupold, not quite as good as US Optics or Schmidt and Bender (yes, I have tried all these scopes). Solid construction, but a bit heavy and bulky. Multiple range finding reticle including mildot and their own NP-** reticles. Probably the best light gathering of the bunch. Pricey but worth it.
US Optics - Best optical quailty I've ever seen in a scope. Plenty of options. Can be bulky and heavy if spec with the larger objectives. Built like tank and unlikely that you can break one. Front focal plane reticles. Lots of reticle choices including new Horus vision ranging reticle. Owner does not have good reputation for CS. His son is much better at the people skills. Extremely expensive. Worth it if you're willing to take chance with CS.
Schmidt & Bender - Extremely good optics, almost on par with US Optics. Sturdy and not as bulky and heavy as USO or NF. Turret adjust in opposite direction to the U.S. made scopes. 34 MM tube so choices on rings are limited. Even more expensive than USO, but looks great on AI AWP.
That's been my experience with these scopes.
