It felt really good to dump AT&T for T-Mobile a while back. Better coverage, speeds, service, features -- and amazingly, about 30% less. I had already made the decision but that 5Ge thing was the cherry on top.
I was an AT&T customer for a long while. But then I realized I strayed from my philosophy of being brand agnostic. So, yes, I switched away also - to whatever the rest of the extended family was using. And the overall deal was better, with better coverage and speed for slightly cheaper.