Originally Posted by Tim_Iowa

Yes, that's the one I've used (and broken). I like it a lot but hate its lack of durability. FYI, it seems to be manufactured by D+D Oberlauda; only recently has it been sold under the Ortlieb name. Rivendell has stocked it for years.

Its failings are:
Clamp -- metal grub screw strips the plastic strap, making it impossible to tighten around the bar. Also, it's awkward to tighten because it's a slotted screw.
Mount -- where mirror attaches to the shaft, the small plastic plate will break if you lean or lay down the bike on that side, and/or the plastic shaft will bend

Ergo, I've broken a handful of these mirrors. However, they have excellent field of view. I still use one positioned horizontally under the Jones bars on my fat bike, but the mirror is pretty well protected in that position.

The B&M mirrors solve the clamp problem because the grub screw is also plastic, so it doesn't strip the plastic band. Also, it's easier to tighten because it's a hex head (hex key included, how German!)
They solve the arm/mount problem by using a metal shaft and much more sturdy ball joints. The mirror will flex out of the way when lain down, instead of breaking like the D+D/Ortlieb.

The B&M mirrors don't have the giant field of view, but the "903" versions do have a nicely sized 3" round mirror. When (not IF, unfortunately) yours breaks, consider a B&M 903.

I currently have a B&M mirror in the bar end of my 'cross bike, and another clamped to the drop bar on my Rivendell. I prefer a position a couple inches lower than yours, so it interferes less with the hand grip position down in the hook. I place the clamp just above where my hand goes on the drop/end.