100% reliable so far. Then again, I've never had a situation where the phone was outside of my house when I've used the app. There have been a couple of times that I thought I had lost my phone in a store, but the app told me I hadn't, that the phone was at home (left in the car as it turned out on both occasions). More often though, I use the "make a noise" feature to cut down the "where's the phone" searches at home. So it's quite useful.
Originally Posted by Jakeea
As for reliablity for outside the house type searches, reliability works two ways, location and wiping. As for location, it's going to be as reliable as GPS and the cell network let it be. So you may not be able to find an exact address if the phone is stolen. But there are cases where people have been able to recover phones in that situation with the app. If you left the phone someplace, like a friend's house, where the phone isn't likely to be immediately stolen if you leave it, or a good samaritan turns it in, even a small inaccuracy in location won't matter because you'll likely be able to ID the correct spot. But even if you can't find the exact place the phone went to, if the app can contact the phone, you can wipe it, which at least protects what you have on the phone.