I'm a fan of helmet mount. I used to use Take-A-Look until I kissed pavement one day and the rigid rod went into my face and the sharp edge on the mirror gouged my nose open about an inch. Now I wonder why I thought it was a good idea having a very rigid metal rod an inch from my eye.

I'm now using a Cycleaware Reflex. The mirror edges are protected and the holder is "gumby" wire.