I have the hydra 26 hd in my 32 and love it. They sell a 4’ arm that you can attach it to the tank stand instead of the tank that made it super simple. The regular kit to clamp it on the top was a pain and took up too much space for my taste.
If I have to choose between AI prime and Kessil, I will take the Prime any day over a Kessil. The kessil spot light will not cover the tank with enough spread, and it will give you harsh shadows for branching coral.