Ok, so I'm reading my magazine (fresh from the mailbox), and there is an article on page 50 that has me very interested in LED lighting. Now, if someone can come on after they read their magazine, and explain it to me . . . that will cut down on the googling that has already started . . .
Heat output is not a big issue with LEDs - They stay much cooler than incandescent or fluorescent lighting. IMHO this can be a blessing or a curse depending on what and where you are growing.
The biggest advantage of LED lighting is the minimal power intake compared to traditional light sources.
The downside to LEDs so far is that there's still work to be done on full spectrum, high intensity lighting for a good price but I have no reason to believe that we will have to wait a long time.
When I was in college in the late 80s, we all were dreaming of blue LEDs. Back then, there were only green, yellow and red ones. These days there's almost no gadget that doesn't have some kind of blue LED lighting in it...