I'm using 4 AI's Sol Super Blue modules on my 120, they are very powerful. The only issue is it is very easy to over power the tank causing bleaching so great care must be taken when using them. And yes when implemented correctly the corals grow nicely.
, it's relatively easy to build an LED
but there is more to it than meets the eye. 1st issue is for them to be more efficient you will have to buy optics for the led
's, 2nd the amount of wiring (depending on how the fixture is built) going to your various controllers and power supplies will be quite a lot and will not look ascetically pleasing, 3rd you are going to have to install potentiometers to control the intensity for the different controllers and colors and still have to use some sort of timer to just have them turn on and off.
After you've completed your fixture you still aren't going to have the features of a professionally manufactured fixture/controller like multiple timers so one can adjust the intensities throughout the day to simulate actual day time conditions/intensities, lunar cycles, thunderstorms, cloud cover etc...
Building your own is cheaper but one must remember when you buy them from a manufacturer you are also paying for the R & D / engineering that went into the product such as the controller, optics and so on. Just my .02
Good luck with your decision.