I must also caveat though, that they do have merits, however when I used Mars II panels, I had bought them about a year a part, and when I fired them up next to each other, you could see a noticeable difference in the overall output of the 2nd panel.. Both were identical in terms of components and even diode placement, so I know I could count on those results.. At the time though, the Mars IIs, were over $200.. Prices have come down quite a bit, but after having grown with all of the types of lights thus far (started out with CFLs), I can safely say that you get the most bang-for-your-buck with COB LEDs, not to mention, you can swap out chips for different color temperatures..
Do you have a light meter, and if so, what are you getting for readings at your canopy?? Just wondering for my own purposes.. I know there are a handful of blurples that perform well, but like I said, I feel those diodes do lose their might after only a few thousand hours.. I run mine at 19/5, and if I do some quick math, it's just under 7000hrs of run time..
Anyway, I guess what I'm trying to say is that it's possible now with some of the current COBs, to outperform even the blurples with GPW, since they run higher PAR/Lumens than blurples, at a much higher efficiency.. However, Chinese blurples are cheap enough that you could literally swap them out yearly, at not much of a cost..
I ordered on the 3rd think I can get them in time for the Mephisto grow
We grow with what we've got 
