In my experience with mirrors, both for myself and introducing other riders, you just have to try a few models until you find what you like. Models that go on glasses, models that attach to the helmet, large, small, ball joints, flexible wire... Every mirror out there has its detractors and proponents. I have my preference, but some people that use this mirror hate it and others think it is the best thing going (I am neither; it's just the least sucky mirror in my opinion).
That said, I will caution you: mirrors that attach to helmets with two-sided tape should actually be crazy-glued in place. The adhesive just doesn't have the oomph for a bicycle mirror, especially when the temperature gets warm.