It's worth noting that not all LEDs provide good light output. I tested a bunch of them that my parents were trying out and some friends, including a few "natural light" varieties, and only a couple of them turned out to be similar to sunlight. Used a homemade spectrometer (chunk of DVD in a box with a webcam) to see the breakdown in light - most have a huge spike in the blue range, the best were nice and even across all the colors.