I don't think the Forerunner is cheaper if you compare similar accessory bundles. The Forerunner is usually bundled with only the HR sensor, but the Edge usually gets the cadence sensor as well. The Forerunner is smaller, which is good if you want a small package. The Edge has a bigger screen to show you more data at once. Also, the Edge has a much more accurate altimeter, if you like comparing your cumulative elevation gain number with your friends.