Those with good credit history who pay their carrier bills on time have nothing to worry about.
AVOID ATT NEXT. You will end up with an A17xx iPhone that will have worse reception than an iPhone 5C.
There are already tests showing that the A17xx phones perform poorer at lower signal areas by up to 75%, and can drop calls consistently. I can tell you I have experienced this personally for the last 3 weeks and have had serious issues getting signal in many places where I used to have OK reception on 3G. These issues will not be evident unless you are in an area with very sparse coverage, so perhaps your iPhone 7 is performing as advertised. If the signal is not less than -110Db, you shouldn't see any difference between the A17xx and A16xx.Not the case here. Mine works better than any previous phone I've owned, including in marginal areas in the national forests.
Sounds like you have some other issue going on. Kind of silly to tell everyone to avoid an entire carrier's financing arm because your phone and your dad's phone don't work for you. Sample size of two give you reason to make a broad claim for everyone across the US? Seriously?
Just curious - when LTE bands did your old phones support which the new ones you got don't support?