Is find my iphone app reliable?

Two days ago i was messing around with find my iphone so i used my girlfriend mobile to check if i could track down mine, but it showed i was like 2 blocks away from where i actually was. Today i was checking again it was totally fine. Is this thing reliable at all?

It is very reliable, the accuracy of your devices signal depends on how accurate it is on a map. The other functions of the app are very reliable, such as remote lock and remote wipe, which I have used on several occasions! Hope this helps!