Below I've added the latest datasheets from the 50w AltaCOB's and latest Samsung LM301b. Both are CRI90 to make it a fair competition. These COB's are not bad (back in 2014) but now they're outdated. Alta does not make new stuff since 4 years, they still sell their 4 year old design which delivers only 80-90lm/w.
Read both datasheets, compare effiency numbers and be amazed...
You have to understand that LEDs are evolving with huge steps. Annual efficiency improvements of 5-10% are the rule. If your lamp were made of Citizen 1212, gen.6/CRI90, the efficiency would be 140-150lm/w, which is good 50% more light than the Alta COB's can deliver.
You got it for free, of course you want to give it a try. But you should also ask yourself why this light is criticized here. Why would anyone have a dislike for you? We do not know you!
But we recognize outdated technology, because here at RUI we are always on the cutting edge of LED technology!
Hell, man! An LM301b in 4000°K/CRI80+ comes to a damn high 220lm/w, that 245% better effiency compared to the coolwhite Alta's with 90lm/w!
Any questions?