The feedback I got from everyone I mentioned the book project to was that "all" LEDs had really bad color, and a deadly green spike was almost always unavoidable, so the lights could "never" be used for portrait work. Ever.
I plodded on, doing experimental shoots and gathering really wonderful LED lit portraits from friends and professional associates across the country. My memory about that time is that it coincided with my flirtation with Canon digital cameras. I had three different models and liked them for three different reasons. But I used the 7D (APS-C) along with a 70-200mm f4.0 Canon zoom to make the image above. We were in the studio using some inexpensive Chinese fixtures that had 512 small LEDs on a rectangular panel. I don't remember the exact price but I think each panel was about $200.
I came across this image of my friend, Selena, recently while cleaning up old hard drives and preparing them for short term storage ( you know, put them in a vacuum chamber, suck out all the contaminated air, seal into a non-porous, anti-magnetic storage containers filled with pure helium....just the routine archival regimen...) and I remembered all the bluster from the ignorati about the inability of LED lights to render a pleasant skin tone. I think a quick custom white balance got us right into the ball park. Not too hard to do if you read your camera's owner's manual... Ah, nostalgia for the early days of what is now very, very popular tech.