What kind are you considering?
I'd say that cost is the biggest downside. If you can overcome the difference in price, the savings in battery draw and hassle of bulb replacement might be worth it. Of course, you do have to install and wire them the first time. LEDs are extremely vibration resistant and most are rated for 100,000 hours (over 11 years continuous use), so it's pretty safe that you will never have to replace them. I've been looking at replacing my crummy incandesant lights with LEDs to reduce maintainance and battery draw. I haven't found ones that fit my application, especially for the red and green navigation lights. I'm curious to know what kind you are looking at to see if they might work for me, too. Brad