I have a set of these installed on the trunk of my year-round sidecar rig, and they have been working perfectly for over 2 years of harsh conditions including rain, snow, sand, hundreds of miles of washboard gravel, etc...
To see a video of them in action you can check them out on YouTube at:
http://youtu.be/ASYTt_4fmTI (Posted on 5/5/11)
I've had mine installed for about a year now (as of 5/09) and they still work just fine. I tie-wrapped them to my turn signal stalks on my '99 Concours. Maybe that dampens some vibration from having them hard-mounted to the body/frame. Or not. But they still flash. YMMV apparently. (Posted on 5/22/09)