I think they work very well when used in addition to HPS lighting. I'm in the middle of a 1030w grow right now, 630w being LEDs, 400w hps. On it's own I haven't tested it yet, but my next grow will likely be only LED lights. The big problem is finding it at an affordable price; but, ebay is actually a pretty smart place to shop for cheap LEDs. If you are really serious I can link you some trusty sellers that have high power LEDs for about the same as a HPS equivalent. 250-600w ranging from roughly $400-$800. But, unlike HPS you just plug in and go. It has cooling fans, it has a ballast all built in. It will get really warm, but never hot, not even close. Imagine a laptop sitting on your lap for 20 min, it gets about that hot/warm.