I'm going to add that having owned a few phones before the iPhone - and all on ATT (not to credit ATT per se) - the iPhone of all the phones has had the worst issue with low signals and dropped calls.
Those always wanting to put the onus on ATT, while they are a contributing factor no doubt, should consider that the radio in the iPhone isn't perfect.
Those always wanting to put the onus on ATT, while they are a contributing factor no doubt, should consider that the radio in the iPhone isn't perfect.