I find that purple plant light really hard on the eyes. Seriously I think I'm straining my eyes looking at plants under these lights, trying to make out if they are green or not.
I find it so disturbing, I don't think I would ever buy it on the say-so that plants like it better.
The plants have to accomodate me as well... I need to see them green or it's no fun.
I just picked up some new bulbs for the T8 fixture(s) - at least I have one fit to use, and the 6500 K was the better color and brightness IMO - also tried out a so called "Natural Daylight" 5000 K and the color IMO was very pink and pretty dim... I'm going to take those back.
Meanwhile I just got two new LED shop lights, delivered today and only half out of the box! Had to eat something before I get down to it. These are only 4000 K but they are 40 watts, 4000 lumens which is better than I can get in a T8. I have used "cool white" ie 4000 K in the past and I thought it was perfectly good for seedlings and/or greens.
This was a case of "price is right" in 4000 K only, not my first choice but I'm hoping to love these lights. As I do not love my fluorescents, no more.