Have to say I`ve junked a lot of mirrors out of sheer frustration.
Finally got the road bike worked out and ended up putting Sprintech drop bar end mirrors on it. As close to perfect as I`m going to find I think. Excellent visability, easy to adjust, small and they stay put.
Wish the hybrid flat bars were as easy! Anything that is an end bar mount means you can`t lean the bike against anything and adds to issues going in and out of doorways. They also interfere with barend choices. I have Ergon grips and the ends aren`t open. And that funny thing that velcros around your grip? Yeah real UNcomfortable!
So I`m currently just glancing over my shoulder. Have tried Ispy and Oakleys - they only apparently work for people with 20-20 vision. Have yet to try any helmet mounted mirrors but am open to the idea. Prime requirements are something thats easy to live with and functional.