That's funny, the picture that you are using for a GPS receiver is a Magellan Explorist 210, it's the GPS that I've been using for biking for the last few years.
But I don't think that it's compatible with your service.
Haha nice pointing that out - our old designer put that together, and I don't think he was fully aware of compatibility issues :) Thanks for pointing it out. However, you can still use the magellen, you just can't directly sync with the site using Garmin Communicator. Uploading a GPX or KML you pull off the unit manually will still work.
But I don't think that it's compatible with your service.