It's getting cold out here, so temps are starting to drop a bit in my grow tent. Rather that adding a bunch of extra wattage with a space heater, I'm gonna take down the bar LEDs and put up my CMH plus QB setup. It will be 20% more wattage, so a few more BTU's, but also more radiant heat hitting the leaves is an added bonus during winter. If it got real cold around here, I'd likely revert to straight HPS during winter. There really is no best lighting source, because it depends on several different variables.