For some reason, the Verizon tower in my neighborhood is flaky. Some times I would get signal in the house, sometimes not. I complained, it did no good. So I went to AT&T and haven't had a problem since.
Meanwhile, it is 10 years later and my friends still complain, some times they have problems getting a signal in my neighborhood.
Note- We are right next to a Major Highway, we suspect Verizon set up their tower for the highway and the neighborhood has to be happy with the overflow signal. So if there are too many cars using Verizon on the Highway, we lose signal and have our calls dropped, again.
AT&T is always 5 bars for me, anywhere in the house.
So yes, AT&T is annoying as hell, but at least I don't have my calls dropped on me.
And I too have a PO Box which I prefer for my official mail address. The family also has several credit cards, two of them "use" the street address. Since I have all the bills and legal notices for all the credit cards e-mailed to me, the address of record is mostly for those times when someone needs a street address associated with a credit card, I give them one of those two. Beats arguing with stoopid systems.