I agree Nanight's marketing can be confusing if not straight up bad. Before doing the research and deciding to get one I'd heard of them but assumed it was some chinese brand. Far from it, I'm impressed with the design and quality.
I don't have a meter but I could set up a camera to do comparisons and run time tests if enough people care. To my subjective eyeball the output is on par with buddies 3500 lumen UWLD or LM canister lights. Although obviously the burn time is much less than the big can lights. Quite short at full brightness if you're used to a can light. I rarely dive it on the highest setting though. The Nanight is (subjectively) extremely bright, the high setting is too bright for a lot of diving and I actually wish the lowest setting would go lower.
The switch and charging mechanisms are a little odd, but fine, and fairly sensible designs. To change the optics you take it apart.
It's not perfect, no light in this "handheld primary" class is perfect. But I concluded it was worth a shot as a decent compromise between price, build quality, battery+led mfg quality, brightness, and run time.