Here's a comparison of LED vs HID lights. Starting with durability - LED's have less moving parts and are much more shock and vibration resistant than HID, not only are they tougher, but they last longer in general, the lifetime is up to 100,000 hours for LED, compared to HID's 25,000 hours.
As for color tempuratures, LED has many options at up to 6500 Kelvin compared to HID's 5000 Kelvin max. The award for being dimmable goes to LED Grow Light. In general, the warranty for your average LED is 5 Years compared to HID's typical 1-year warranty.
One of the biggest factors is definitely costs and though LED's have a higher upfront cost they require much less maintenance than HID, so over time LED usage costs less.HID is more cold tolerant to tolerant down to -40 degrees compared to LED's -30 degrees. And finally, the light speed of LED's are instantaneous while HID takes a bit of time to warm up.
