Man I would be so confused if I were starting from scratch right now.
For a new small room build I would absolutely be tempted to run LED. Already having HID and being happy with it is a different story though, it's going to take some real world results shown to me before I'm convinced to drop a pile more money on replacing my lights.
For me, the 40% power savings doesnt mean much, I simply dont care about that. My power is cheap. For my setup it would save me maybe $25 a month. Big whoop.
The cooler operating temperature doesnt mean much either, if anything it's a negative as I need the heat for 8 months of the year.
What I want to see is growth rates, dry yield per sq/ft of grow space, bud structure, cannabinoid and terpene development etc.
As far as I can tell, high quality (more expensive) LED is just starting to match HID in those areas, not blowing them out of the water.. But just being equal. Some may be exceeding HID but not by much. When LED starts to far exceed the growth rates, quality of finished product and dry weight yields of HID, then i would switch, if, and it's a big if, its affordable to do so. But last I checked, replacing my 2K HID which currently illuminates an 8x8' room stadium with
HLG, I'd be looking at a little over 4 thousand dollars for 4 boards to essentially do the same thing I'm already doing. My only benefit would be not replacing bulbs and reduced power on the lights. But I'd have to heat my building which offsets that. And then how long will the LED go before the whole unit needs replacing again? Too many iffy variables for me just yet.