This is a great phone, EXCEPT when it isn't. Mine often gets into a mode where immediately after pressing Send to start a call it just plays a little tune and immediately disconnects/does nothing! This happens time after time to any number. This has happened 7 times over 2 months of ownership.
Samsung support seems to think that this is perfectly OK. Their solution is to "reset network settings". That works, but it also (for me) involves adding 5 WiFi passwords and 5 Bluetooth devices.
First and foremost this should be a phone that works the first time and every time it is within range of a tower. It doesn't. If that happened during an emergency situation I'd definitely sue Samsung for every penny they have. If you multiply this problem by all the users of this phone I suspect that the odds of this happening during a life and death emergency are 100%