Congratulations to these geniuses! Without them, our favorite hobby would be a lot less colorful. 
http://beta.slashdot.org/story/208175
Not so good. White LEDs upset the Circadian clock in the human body and are screwing up our sleep patterns.
I would avoid exposing your eyes to the output of white LEDs after about mid-day.
As an example, both Boeing and Airbus are looking into white LEDs messing up flight crew sleeping pattens after events that were tracked back to new sleep issues.