Brighter is pretty much always better, just don't burn the plant with heat when not an LED - and, if LED, if it's like mine with separate red, blue, IR, and UV bulbs it isn't good to get too close over more than one plant because one will be under a blue light while one cooks under the UV one etc... mine is pretty focused overall so like I say I'm not convinced I can fit too many plants under it later on the later stages without a mover at least, and even then it probably won't penetrate to lower leaves (better yet buds!) as well as an HID would.