My company makes LED commercial fixtures. The most important thing is the heat sink. The amount of heat sink area needed is dropping on a almost weekly basis. You want to make sure you are getting the latest LEDS. We use rebel LEDS from lumileds. You need to find out the surface area per watt needed for the heat. The other problem is that if they run a little hotter than spec they may only last 5 or 6 years instead of 10. That is not a big deal. I use 1watt LEDS for my tank and have no noisy fans and they work fine. You can check out this site (nothing to do with my company).
http://www.luxeonstar.com/, Good luck, Don
