I'm from Denver.
I have a rock solid Rezound experience in almost all situations in almost every location in the metro area.
Did a driving vacation in Black Hills of South Dakota and the phone acted really weird.
It would regularly be on a strong fast 4g signal and then it would go away.
Nothing I could do would bring it back.
I tried toggling the wifi on and off.
I turned on airplane mode.
Turn it off and the airplane icon in the notification bar would not go away.
I check in settings and, indeed, airplane mode is off, but icon still there and no data signal.
The only way to get it back was to reboot.
Then I'm back on a strong 4g or 3g signal again.
Vacation over, back to Denver and all is back to normal.
Network is solid. Flight mode toggle works just fine.
I just post this for my general knowledge and, if anyone knows a solution, for those who might experience this in the future.