I'm not aware that any light manufacturers acctualy produces le diodes.
So, it's all philips, bridgelux, osram, cree, etc.....
Also, not aware of 10,50,100 chinese guys manufacturing diodes at home garages or basement. So again, its philips, bridgelux, or any manufacturer that acctualy manufacture diodes.
Only difference is quality and consistency. Ecotech or kessil gets highest quality diodes, from same BIN, with identical output, spectrum, spread, etc....
The rest gets the rest.
So one, if lucky, can get same bin with random purchase off ebay, like ones in any high end unit. Not big chance, but, still it is.....
Second is quality of drivers, cooling, etc.... Again, big manufacturers use high end components, high end thermal solution, rest use the... Well, rest
Third is software (if any). Big names spends great amount of money for peogramming app, features, cuatomization, etc.... Small ones have basic limited app, which is ok, because light itself is limited in features and possibilities, either because thermal issues, driver quality, or, diode quality....
Fourth, and most important is marketing. How many units does "insert big name here" sends to various people - reefers, youtubers, influencers, companies, sellers... Not really matter does "insert random internet dude" have any relevance,knowledge, reputation in world of reef tanks.... He have gazillion followers, and his name associated with "insert big name product" is great marketing, object of desire and wet dreams all over the world.
Small(er) manufacturers dont do that, or at least, dont do that on any scale that can have impact on things.
I see that noopsyche lights are very good, people have high opinion on them, sadly i live on wrong planet to ever have chance of getting one, but...
How many giveaways they had so far, that is marketing. Talking about product is marketing.
Imagine that this company who sells these knockoffs decide to take 50,100 or 500 units, and choose random people from r2r, and send them lights.... How many times will they improve selling rate, if people here read how some of us are happy, fascinated, and have great reef tanks, great coral growth and color - using these....
But, they dont do that, they really dont care.... They have low production cost, relatively low selling cost, so... If someone buys great, if not.... No problem.
So.... Quality difference, yes, for sure, but there is much more. And quality difference then is not that big or important.....