The big time issue is that to both grow and pop with LED, you need a more daylight spectrum during the day and then shifting to bluer for your viewing pleasure during the evenings (or whenever you want to view). Cheap black boxes are hard/impossible to program, so you have to do it by hand.
Blue-only for POP is not good at rendering color in the long term, so you just cannot leave them there. This is why something like a RB or Orphek can do well because you can turn it on during viewing time to look at the pop while the MH (or your cheaper LEDs) are more 14k (ish) the rest of the time. If you buy high end LEDs, then you can program them... but that is a different level of cost.
Blue-only for POP is not good at rendering color in the long term, so you just cannot leave them there. This is why something like a RB or Orphek can do well because you can turn it on during viewing time to look at the pop while the MH (or your cheaper LEDs) are more 14k (ish) the rest of the time. If you buy high end LEDs, then you can program them... but that is a different level of cost.