Just got a Nerd and personally I love the thing. Super easy to see my speed and it is just a simple device. I have the backlight on mine and it mounts on my stem. It's really nice to see my speed because I ride for fitness as well as commuting. The scrolling odometer looks killer.

I am averaging around 20-24 mph out there and can hit 30Mph...which I guess is good..who knows..the main thing is figuring out my RPMs from this information, and I still do not quite know how to pull that one off.