I have the Blackburn Road Mirror. I can't use a barend mirror, because I have barend shifters. The Road Mirror is okay, except the mount isn't very solid, so it shakes over the smallest bumps. It needs to be beefed up, or triangulated somehow. (Are you listening, Blackburn?) I have a barend mirror on my mountain bike that is much more solid.

I would no more ride my bike without a rearview mirror than I would drive my car.