I made my PhD on LEDs and I totally agree what ImStricken said about the huge quality difference. In average, current good quality LEDs have 80.000 hours of useful lifetime (the industry uses LM70 standard, which is the time and LED sustains the %70 of its initial light output. So if an LED has LM70 of 80.000 hours, that means, that LED will be have 70 percent of its initial lumen output, brightness, for 80.000 hours...after 80.000 hours, it will still give light but not as bright as before...and in general an LED can run for 100.000 hours).
When you are planning to spend money on LEDs, ask the company where The LEDs are coming from?
If it is Philips Lumileds, Osram OPTO SEMIsemiconductors, Nichia, Cree, go for it...if not STAY AWAY.
By the way, Osram introduced first fog light application for Ford Mustang (
http://ledsmagazine.com/products/36404). the future of lighting is LEDs, but just be aware of the cheap products in the market.