You have tried successfully to use ATT for your needs, the only thing I would suggest would be a backup on another system. Having a personal line on Verizon service for occasions when ATT just doesn't have local service.
You will still have occasional areas that may pose a problem, but between the two systems you should have far fewer dead zones rather than keeping all your eggs in one basket.
And the addition of a "Weboost" type of unit will supposedly make those cases even fewer.
How far out of towns and off the interstates you wish to travel is likely the determining factor in how often you will need the additional tools, and only you know how remote you wish to live.
