The light is bright and highly visible - it's an easy way to make yourself more easily seen. I like having two sets of brake lights (stock + this light) because I think a single light makes depth perception more difficult for drivers.
But: it doesn't mount to a WA license plate without having to cut away some of the plate (the wires coming out the back are too high on the light). Also, condensation collects on the inside. I returned my first one for this reason, and Aerostich sent me another - I added extra shrink wrap to the wires on the second one, and protected the back from spray from the tire, but moisture still gets in (I suspect through the hole where the wires exit the unit).
I'd buy another, because it's the only light like this that I've found, but if another company made a similar one, I'd try theirs first. (Posted on 3/26/10)
The Versa Light was easy to install and folks following me tell me it has improved visibility of my motorcycle. However, after the first rainstorm I rode through, the lens fogged leaving condensation underneath. Not sure what the long term affects it will have, or if it can be sealed against future vapor leakage. (Posted on 5/15/09)