There exists some concern that the replacement of individual diodes is complex from what I have read. Also, they are really pricy. Sure that someone else will chime in as i have never actually seen one of them.
yes they are very very expensive a 72 in light is around 3100 dollars but they seem very versatile in there lighting abilites and they use less enegry put oof less heat and eliminate the need for a water chiller idk,they seem kinda cool.
I am actually building my own as we speak. It won't be anywhere near as cool as the real thing. And it is only for a Aquapod 24, so not as many LED's, but I will let you know how it works.