The little screen is not much use for on-bike navigation, even with reading glasses. If you zoom out enough to see the "big picture," the screen is so crowded that you really can't see the little roads you want to ride, or read their names. So you still want paper maps for that. For navigating a route you've programmed, you get a tone and a big arrow before each upcoming turn. Depending on the light and how much magnification you need, you may or may not be able to zoom in enough to read the road names without glasses. It's plenty for me.

For me, the bottom line is that if I need to look hard at the map, I really need to pull over (car, moto or bici), and once I'm pulled over, I can pop out the credit-card-sized magnifier I keep in my jersey pocket if I need it. (Gotta have that for restaurant menus, anyway. )

Not that I'm trying to enable you or anything. But did you see how much cooler the new Garmin 800s are?