I's sure there are some that will disagree with me about this, but I have avoided LED up until now primarily as a result of the
Inverse Square Law of Light
View attachment 606318
Basically, this translates to bud density IMO. This is the ONLY advantage (in terms of plant growth) I find in a 1000 watt bulb vs a 600 watt bulb aside from a slightly larger coverage area and depth. Which is the next things this factors into. If you are growing your plants somewhat short and stocky, low-intensity, high-volume LEDs will probably be quite effective. Others can speak to this better than me.
On the other hand, if you are trying to replace a HPS fixture in a flower environment, you will need a relatively high point source to penetrate and effectively illuminate taller plant's potato size nuggets. LED's, to me, are really interesting in that you can achieve this a couple different ways.
I have seen some people simply hang LED's everywhere around a plant for example so that there was always a relatively intense source of light close by to whatever needed growing. This seems like it works pretty well for a closet situation or cabinet grow for example where plant height is limited and other factors are in favor of that type of design.
Now, technology of LED's has improved tremendously. Not only are they more efficient, but they are brighter as well. I am not as abreast of single diode technology, but I have read a little about 3w, 5w, and 10w diodes. The 3w diode, capable of penetrating 3-5ft effectively, I think is really where the peak efficiency to penetration is found on today's current technology based on my research. This is mostly a product of thermal dissipation. 5w and 10w diodes just put off too much heat and as such can not be packed as tightly together without increased risk of thermal failure. However, as per the illustration above, they would of course have greater penetration. Again, I haven't yet used any of this technology, I have just thoroughly considered it over the years and watched it develop.
Fast forward to COB technology. I didn't really see it going this way, but it seems logical. These are actually packing 100-1w diodes on a single chip. Because they are so densely populated you can essentially consider this "r" in the above illustration. So, they effectively work together like a single, very bright point source. The coverage and penetration should be much greater as a result of this as well.
I can't really say this next part better than wikipedia...
https://en.wikipedia.org/wiki/Photosynthetically_active_radiation
Yield photon flux[edit]
Weighting factor for photosynthesis. The photon-weighted curve is for converting PPFD to YPF; the energy-weighted curve is for weighting PAR expressed in watts or joules.
PAR as described above does not distinguish between different wavelengths between 400 and 700 nm, and assumes that wavelengths outside this range have zero photosynthetic action. If the exact spectrum of the light is known, the photosynthetic photon flux density (PPFD) values in μmol/s can be modified by applying different weighting factor to different wavelengths. This results in a quantity called the yield photon flux (YPF).[3] The red curve in the graph shows that photons around 610 nm (orange-red) have the highest amount of photosynthesis per photon. However, because short-wavelength photons carry more energy per photon, the maximum amount of photosynthesis per incident unit of energy is at a longer wavelength, around 650 nm (deep red).
It has been noted that there is considerable misunderstanding over the effect of light quality on plant growth and many manufacturers claim significantly increased plant growth due to light quality (spectral distribution or the ratio of the colors).[4] A widely used estimate of the effect of light quality on photosynthesis comes from the Yield Photon Flux (YPF) curve, which indicates that orange and red photons between 600 to 630 nm can result in 20 to 30% more photosynthesis than blue or cyan photons between 400 and 540 nm.[5]
The YPF curve was developed from short-term measurements made on single leaves in low light. Some longer-term studies with whole plants in higher light indicate that light quality may have a smaller effect on plant growth rate than light quantity.[6]
What I take from this is that overall intensity is maybe slightly more important than specific wavelength....but I think the jury is still out on this. From the standpoint of the specific wavelengths you chose vs "white" COB lights, white light is just a combination of all the visible spectrum. So, you will be covered on all fronts with a "white" light. That being said, there are different colors of these lights expressed as ~6500k - 2700k. Higher numbers are more blue, lower numbers are more red. So just like floro's, you just choose a COB based on the application but you can expect good performance in any case because these are relatively efficient in both the red and blue spectrum.
I hope this was helpful to you. There are numerous threads with good info about LED's from people a lot smarter and more experienced than me. I know a little about physics and engineering, so I just try to lend that perspective.
Happy Growing and Good Luck!