Last year, when I started bicycle commuting, I put a bar-end Mountain Mirrycle mirror on my commuter bike and also rode with a Take-A-Look mirror clipped on to my sunglasses. I wanted to try both and see what worked best for me, since I ride in traffic daily.
For me, the Take-A-Look is much better, and I found myself using it 99.9% of the time. It is a higher-quality, less shaky image, and you can look quicker and also scan a sweep behind you if necessary. When the bar-end mirror fatigued from being leaned against stuff and finally fell off, I didn't replace it.
I hope you find what works for you best. Mirrors can be an important safety benefit, particularly when riding in traffic. I encourage you to consider the Take-A-Look mirror. They cost about $12, and they clip on most any glasses. I use one of them and switch between sunglasses or clear safety glasses, depending on the ride. Good luck!