I know verizon has a definite advantage over att lte service. It's super fast. But besides LTE service...Why do I keep hearing very good things and very bad things about att? I don't get it... I never see that with T-Mo nor Verizon...
ATT was the first carrier to get the iPhone (and had it exclusively for about 4 plus years) and their network was not ready for it. As it helped it's growth, it also caused ATT problems and complaints in major metro areas. Drop calls being the most common.
I remember listening to an Aaron Rodgers interview on the Jim Rome show about 3 years ago. He kept dropping the call and he had the iPhone on att.
Now me, I live in an area of California that I have had zero problems with ATT and drop calls, but when I would drive through Los Angeles and was talking to somebody my phone call would drop occasionally. One day I was having a conversation with a person while on the freeway and I had 4 drop calls in about 5 minutes so I told the person I would call them later when I get out of the area. That can be frustrating especially when you have a very important phone call.
The other main positive for ATT was until iPhone 5, ATT had the fastest data with regards to the iPhone. When the iPhone 4 finally went to Verizon, the main issue was Verizon's 3g data network. Voice wise I heard very little complaints to drop calls on Verizon. ATT really did at the time have the fastest 3g/3.5g network and it worked very well. In many locations I would run speed tests and consistently get around 7mbps on iPhone. Now with LTE Verizon is king and probably be king for a long time.
Now things are better but ATT still leaves a bad taste in people's mouths over these kind of issues. Since most of the time I have had very little problems with ATT and still sticking with them.
If ATT did not have a fast 3g network I would have probably switched over to Verizon. I do not care about voice, I care about emails, attachments, and how fast I can get to my data.
When you get an iPhone and you realize how gimped it seems(and I have seen people return their iPhone 4s back to Sprint because of their bad data network), it makes a night and day difference.