I've got a mars 300 in a 4x4, but I'm only growing 1 plant at the moment, and it's loving the amount of light it's getting. I have a second mars 300 if I need it for when I have more plants or I move into flower. The nice thing about the mars is that you can run them until the board burns out and either buy a quantum board or some cobs to replace it with, and not have to buy new drivers and heat sinks.