I've got a Garmin 500, 520 and the Magellan 315. The Magellan is about twice the size and weight of the Garmins. I bought the 315 for it's mapping capabilities. I set up some test routes and it failed miserably. Told me to turn the wrong way several times. Got really confused when I didn't do what it requested. I gave it another chance a few weeks ago and put a 35 mile ride from the Great Western Bike Rally into it. It worked perfectly. I'd say, for that price, I'd give it a shot. That's a great deal.