http://velocomputer.com/faces/mainpage.jsp?uri=home.jsp

Looks like you purchase a $199 bluetooth transmitter, that measures wheel speed, and cadence. That integrates with your mobile phone, it's GPS, etc. and provides you with a lot of functionality, while carrying only a phone. (something I have to do anyway as a systems administrator.)

Do any of you guys have one of these units? If so do you think the device works well, or would I be better off buying something like the Garmin?

Thanks in advance!