Hi,
I am using my Etrex-30 for mountainbiking and I am very pleased with the device, especially the battery life. However, I am a missing a few features on the Etrex, for example courses and workouts.
The Edge 810 seems to have all these nice features and even more, but unfortunately this device has an internal battery pack that cannot be changed. I really dislike this, so no Edge 810 for me.
How about combining the two and create an Edge Penlite? It will have all the nice features of the Edge 810 and the battery life and battery flexibility of the Etrex. I would definetly buy it!