I see these threads all the time comparing different types of light....LED, MH and T5s....I recommend people read this to learn a little more about the science of light and how it matters to corals:
Feature Article: Light in the Reef Aquaria — Advanced Aquarist | Aquarist Magazine and Blog
I believe the main reasons people struggle with LEDs are:
1) Acclimation to a new type of light (some corals look good in some spectrum of light and look bad in others--same goes for intensity)
2) Most LEDs lack the actinic spectrum and thus many corals lose this critical spectrum of light (see article above)
3) Remember, light is light whether it comes from a MH, LED, or T5.....what matters is the spectrum and intensity.....
cheers,
Darren