I have a DeLorme Earthmate and it's nice, but rather large in comparison to the Garmin Edge (200, 500 or larger 800) which is built for cyclists. Both can be used on multiple bikes with a bike mount. Really depends on which one is more user-friendly for you.
I've been really enjoying my Garmin Edge 700 with the heart rate monitor for the past 4 years. I bring it on every ride so I have a nice log of all my rides. They don't make it anymore so if I had to get a new one it would be the 800.