I forgot to mention the main reason why I went with the Garmin 510. It can sync with your cell phone and you can start a live track. You can choose who you want to send a live track email to in your options. The live track allows my wife to see where I am, my speed, ect, along my ride. This allows me to ride and her to see where I am at, my speed, direction, and if I am still moving without calling me. This is the feature that convinced my wife that she needed to buy this for me.