AT&T provides good coverage IF you live in a city. Outside suburban areas they suck. REALLY, really suck. I'm near a major interstate and have Verizon Wireless LTE. Our dear friend who visits and works for AT&T is lucky to connect to the EDGE network.
As to the phone data issue...my dumbphone went swimming a few years ago before VZW swallowed Alltel. A friend offered me a like-new Blackberry but I would have been forced to accept a data plan. I didn't want a data plan because at that time we didn't even have 2G nearby! Why on earth would I pay for a data plan I couldn't use? I ended up, like many others, getting a cheap phone on eBay and paying for activation.
Our family has 3 dumbphones and after my husband's work discount we pay less than $100 a month. At home and where there's wifi we use tablets. VZW and their ilk can go zorch themselves and their data prices.