This works fine between my wifes iPhone and my own, but what make it special is the built-in ability to send a link to someone who doesnt have the app (or even an iPhone) so they can see where you are. GPS apps in general chew up battery life but this app has some configuration options to help with that problem. Ive had this app for about 8 months and its been great so far.
DavidAdams about Family Tracker, v2.4