Yeah, I now have a mish-mash of lots of different lights, too....nothing at all wrong with that. But I'd rather have one light that can evolve along with technological advancements (which seem to happen constantly!). I don't really like the idea of trying to re-sell last year's grow light and give out my address in the process -just paranoid that way, I guess. So, I tend to accumulate grow lights!
I'm not arguing in favor of bulbs -in case I come across that way. I'm merely pointing out that bulbs allow the user to change the bulbs as bulb designs expand....ballasts are the same way....easy-peasy. Maybe when LED technology evolves to allow ANY user to "screw in" (so-to-speak) a new COB or a new board, etc., we will start to see more of a crossover.