look at this cool mirror!

[HillSlugger]

I've got a mirror like that (not sure if it's the exact same one) and like it quite a lot. It gives a pretty good viewing area.

The first mirror I tried was one on my glasses frame. I found the viewing area to be so small that I never knew exactly what I was seeing. I ended up spending too much time trying to figure out the mirror view and not enough time looking forward. The bar end mirror has worked out much better.

Edited to add: vibration has not been a problem and it holds its adjustment well, except when I bump it on my leg or top tube at rest stops.

Edited again: unfortunately, when I have my aerobars clipped on, the aerobar pad blocks my view of the mirror. I have not yet figured out a solution for this.