One disadvantage:
Apple removed the "send a message" feature from the "Find My iPhone" app. All you can do now is send a sound. That's cool if you are just trying to find your phone that may be lost under your bed and on silent or something but if you lost your phone in public somewhere and someone found it, what is sending only a sound going to do for that person? "Hmm I found this phone but it keeps making this noise!!?!??"