Overall, this app does not work as well as the other devices in our Personal Locator Beacon review. It is intended to help keep track of family and friends in urban environments with great cell coverage. That said, in certain situations, it could work as well or better than a SEND device (Spot Gen3). We have been in situations where a solid 3G signal can be had on our smartphone, but no satellite signal can be found. Therefor, we recommend using this, or a service like it, in conjunction with a SAT messenger.
If you don't have an iPhone, you can use a similar Find My Friends! app for Android. Strava also offers a similar service to paying members.
Apple iPhone Find My Friends Review
Cons: Only works when your phone is on and has an excellent data signal, it does not connect you with emergency services
Bottom line: Doesn't work out of cell range. Very useful in cell range and a good backup if your SAT messenger loses sattelites.
Weight w/ batts oz/g: N/A (weight of an iphone)
Battery Life (hours): N/A (battery life of an iphone)
RELATED REVIEW: Best Satellite Messengers and Locator Beacons
Our Analysis and Hands-on Test Results
In thick trees along a steep cliff band in in the Alps, where cell networks are massively more expansive than in the rural U.S., we were able to check our email, make a call, and check to be sure that our buddy Carson was still sitting on his couch in Waialua, Hawaii. And he could have checked his app to see that we were camped out in the trees there, below a massive BASE jump near Chamonix, even if I was unconscious and not able to pick up the phone and dial. Meanwhile, we had no signal on either of the SPOT devices or the Garmin. One thing that became very apparent using the inReach and SPOT devices was that without a very clear view to an open sky, they do not work well at all. A phone well inside a 3G network area, on the other hand, works under cover, indoors, etc.
In another instance, we were backcountry skiing miles south of Kirkwood Ski Resort in California in a 4,000-foot deep canyon. While avalanche danger was not high, it was steep terrain with a good chance of hitting rocks (multiple times) if you lost control. Miraculously, we had good cell coverage. We were in a group, but had this been a solo mission and we had fallen and been badly injured, it would have been easy to find exactly where were were.
While at first we were skeptical and considered not even including it, this is an interesting extra option for people who travel in areas where mobile phone coverage (we're talking solid signal) is plentiful. Clearly, however, this could never be considered as a standalone emergency messaging device. Don't even think about relying on this app for anything other than entertainment and stalking your friends who are willing to go through the setup process.
— Matt Gerdes