I'm loving my 100w HLG100's and HLG65. I also got a Chinese knockoff on eBay which is almost as good, by Yuson. Actually I got 2 Yusons for $40, because I measured the current usage on the first one and it was only 65w. I wrote a bad review on eBay because it was advertised as 100w. They offered to send me another if I took down the bad review (they did, and I did). The replacement uses 105w. So i got 105w + 65w for $40! The HLG lights have a more even pattern of light. The HLG65 is enough for a small plant or for seedlings. The 100w at 15" is good for a plant that's 2' wide as long as it has a flat canopy, maybe a little more in a reflective tent. I'm doing 6 smallish plants at a time, with 4x100w and 2x65w, and I'm very satisfied.