Eyeglass mounted mirror for me. I have tried the bar end mount and a helmet mount, neither worked for me. I kept hitting the bar end mount with my knee and never got the helmet mount in quite the right place. Read a tip awhile back about using those tiny zip ties to secure the eyeglass mount to the eyeglass frame should the little brackets fail. Tried it this summer and it worked well, saving a mirror from the trash.
Deany
"A girl can never have too many bicycles"
2008 Specialized Ruby Comp
2012 Specialized Vita Elite
2013 Specialized Myka Elite