I know a few people who have tried LED, and talked to many suppliers, and I would stay away from LED. They simply do not have it ready. Other than traditional lighting, the only alternative that has impressed me is induction for veg.
not sure where you have been looking
leds seem to be at an interesting stage now
they are able to compete with hps and in some cases out yield hps
the downside i can see at this stage is the initial cost of leds and the durability of leds
i have hps ballast that are 15 years old that still work
bulbs last 2-3 years before they need replacing and cost next to nothing
led may not be able to compete with this but can be fixed relatively easily
for me personally i will try them at some point when i decided what light to test first
the novelty of growing without the need to move such a huge volume of air
through the plants to control heat would be interesting
folk growing on larger scales each led will pay for its self and some more on the first harvest
an advantage with led will be rooms can be filled without heat issues
the present and future looks bright for leds