I actually have both Kessils and AI Sol Blue on my 48x24x24 120 gallon tank.
I started out with 2 Kessil a150w Sky Blue on my 65 gallon (36X18X24) and was somewhat happy. I said somewhat because even with the 2 Kessils, the tank looked dim. I had to supplement with 2 T5s to even out the spread. It was probably ok but I was just used to the T5 brightness. The Kessils is a spotlight which gave very dark shadows under caves, etc. I will say that I had some SPS frags that showed some growth during the 3 months that I had those lights on that tank. I think I had a birdsnest, green slimer, and a montipora digitata that showed good growth. I also had a variety of LPS and softies (frogspawn, torch, candy cane, lobos). In addition, I had a derasa clam that seems happy.
Then I had the upgrade itch . . .
I upgraded to a 120 and used the 2 Kessils on that tank supplemented with 4 T5HO. I was going to buy 4 more Kessils but when I did the math, it was actually somewhat cheaper to buy 2 AI Sol Blue than 4 more Kessils. 4 Kessils is $265x4=$1060. 2 AI Sol is 399x2=$798 plus $75 for the controller total = $873. It was about $190 cheaper to go with the 2 AI Sol but it gave me a dimmable controller that lets me enjoy my tank longer. What I mean by this is that I started my light from 7am to 11pm; slowly ramping up to full intensity at 3pm to 10pm, then lights off at 11pm. With the Kessils, it was on at 3 and off at 10.
Now I have 2 AI SOL Blue and 2 Kessils a150w on my 120 gallon and it looks great!!!
Why did I think I needed 6 Kessils, you might ask? I actually tested 2 Kessils on 1 side of my tank and thought it was still too dim.
Things are continuing to grow and I'm happy with the setup.