LED = light emitting diode
LEC = light emitting ceramic (aka CMH ceramic metal halide)
LEC is an improvement on old technology that is metal halide bulbs. It provides a superior light spectrum and apparently improves quality as a result. It is a white light and Greenie is kicking ass and chewing bubblegum with his... It also has a unique vertical mounting in its reflector (315 not the 630 which are horizontally opposed), which I believe improves it even more.
LED is extremely varying. They are more efficient in general, less heat as a result. They are the future. White light LED more specifically. LED can get closer to the sun's spectrum than any other technology. They are still too expensive, IMO. I am looking to pull the trigger on a 9 light cob when the prices drop more.
Hope this helps...