I'm always curious how I look (how visible I am) on my bike at night. I really want to get in my car and watch someone else ride my bike. Anyway, tonight I settled for dropping my backpack at my driveway, facing down the road. Then I rode my bike to the end of my road and I could still see the flashing light. Road ID claims that you can see the light from up to a mile away...that might be a little far fetched or under perfect conditions or something. This light was still very visible from a quarter mile away. The light is supposed to be omni-directional, meaning it doesn't matter which direction it's facing - you'll still see it from any side. I pushed my backpack over and looked at the light coming out of the side of the Supernova and it was not nearly as bright. You could only see it faintly at about 100 meters.
I'll see how well it holds up...it's supposed to be waterproof down to 300 feet (a light like this would be sweet in low-vis water). It's small enough that I can keep it in my backpack. The packaging says that there's a bike mount for it, but I can't find one on roadid.com. If I like it, I'll probably get another one or 3 of them.