Note that there are 3rd party solutions for the Pebble (straps that use their extension/accessory pins to add GPS and a bit more juice) and that Pebble plans to

Note that there are 3rd party solutions for the Pebble (straps that use their extension/accessory pins to add GPS and a bit more juice) and that Pebble plans to release the Pebble Core in January - a tiny wearable Android device with GPS included. So you should be able to go out with your Pebble + SomethingElse and leave the phone at home, if we're talking GPS or tracking. Disclaimer: I own a Pebble Time, I backed the Pebble Time 2 and the Pebble Core.