They cost, but they're really unique--some refer to me as "the guy with the gauges". I wanted a tach, and was going to spend, so I figured why not. I've met only one other rider with them, and by sheer coincidence ended up sitting in the next cubicle at work.
I had to replace it once under warranty, the speedo got whacked. I hear it's not uncommon. I have the big tach version, but in retrospect maybe the large speedo would've been more useful. I'm not sure they fit newer Monsters like yours. Older ones without tachs created some demand but not anymore. Double check on that.
Thanks for the feedback everyone. The design is definitely unique. I don't know why more people don't have it on their Monsters.
Sivan: Thanks for posting the image. Is that you in the mirror? You have yourself positined perfectly! If you have any images from the side and the front, I would really like to see them. At your convenience.
The camera is a Canon PowerShot G3. It was shot at a secret training facility by a buddy of mine and he's been shooting for fun on rides for quite a while. Shoot enough and some shots will turn out nice, toss the rest. No special planning required but some patience.