I've seen it in person with different light output modes on lights. I've seen it talked about more scientifically on wikipedia, but didn't find it in a super quick search. I know I've read through it before. I couldn't tell you more info than I'd get searching google right now.

There's no doubt that if you're willing to live with less reliability, waterproofness, etc that off-brand lights are cheaper.

However, there's also no doubt that the Light and Motion Lights tend to be rated fairly accurately, while the off-brand lights tend to be rated at about twice what they can actually put out. A 1300 "lumen" light from a company in china likely puts out about 650-750 lumens.

Like I said though, I've chased through about $1,500 worth of bright lights, and there is no point in getting a brighter light with a less-good beam pattern. The only reason the Seca combination works is because they happen to make a good beam pattern together, with no hotspot. They're all usable and sitting together in my garage, but I continue to prefer the shaped beam lights.