I was in the exact same boat you are in right now. I had the same budget in mind and almost went crazy trying to pick a good led for my tank. After doing an extensive amount of research I decided to try T5 lighting. I had led lights before although they are very nice and easy to work with. The T5s are much more crisp I'm glad I made this purchase. I have never owned any of the new LED lights on the Market, but based strictly off of research I'm going to say Kessil because Kessil has a team of scientist that work for them that manufacture their own LEDs; what better company to buy from then the ones that know exactly what your corals need. That is why Kessil lights are a bit more pricey. I would go with Kessil 700 over the AI 52 HD and Ecotech and if the Kessil 700 is too much I would go for AI 52HD over Ecotech, because AI and Ecotech are made by the same people so essentially you are getting the same product at a reduced price because of the name.