For as long as we can remember, AT&T has been rated the worst carrier of all carriers by Consumer Reports. This annual report placing AT&T last is as consistent as Christmas being on December 25th every year. So yes, for this year, it's the same story. AT&T is the worst again. And Christmas is on the 25th of December.
Verizon was the highest-rated carrier in Consumer Reports, scoring well for voice and data service quality and "also for support attributes like staff knowledge and resolution of issues." See, I care about customer support but I care much more about having good voice and data service so I never have to call customer support. Verizon has both! AT&T seems to have nothing. According to Consumer Reports, Sprint, T-Mobile and AT&T all received "middling to low marks" in voice and text service quality. Taking into consideration of everything, AT&T was the lowest rated carrier overall.
However! It's not all that bad for AT&T. AT&T actually had the best rated 4G LTE network. LTE users on AT&T reported the least problems out of all the networks. AT&T has recently expanded its LTE coverage to 103 markets covering 150 million people (that, of course, doesn't mean everybody is using a 4G LTE device though) so maybe when everybody moves to LTE, AT&T will be able to climb out of the familiar hole of being rated last place. Maybe. [Consumer Reports]