I've tried them all and I keep cycling between them. I recently went back to the Italian Road Bike Mirror and, for the first time, got it properly and perfectly positioned. This is the best in my opinion. By far. But you need to take the time to set it up properly.

For helmets/glasses, it has to be a helmet mirror. I *hate* glass mount mirrors it just seems and feels awkward. So I use the HubBub Helmet mirror. HubBub Custom Bicycles Online Store - Product Detail

J.