I'm looking for a nice light to use while biking on dark trails and unlit streets, and came across the L&M HID. Does anyone have any experience with the two battery types in this application (Li-Ion vs NiMh)? The Li-Ion is attractive because of its lighter weight and larger capacity, however I know that lithium batteries can be dangerous, and don't know how well they stand up to vibrations and standard abuse that a MTB will receive. Basically, is it worth the extra ~$70? All opinions are appreciated.