I started out with AT & T 12 years ago. They were then bought out by Southwestern Bell, then Cingular and now back to AT & T. Obviously, I have been happy with them for the most part or I would still not have their service.
They offer many different rate plans. The plan we have is the Family Plan. With that plan, we have a certain about of minutes shared by everyone on your plan. My husband, my father (who lives with us) and I share our minutes. It is convenient since their is only one bill to keep up with. The minutes that we don't use rollover to the next month and can be used during the next 12 months in the event we go over our alloted minutes.
Our favorite option on the plan is free mobile to mobile. That means that we can call any other AT & T Wireless customer in the United States and not be charged our minutes. Most of our family and friends have AT & T as well so we don't have to worry about how long we talk to them.
They also have options for text messaging and internet use, but we use our phones strictly for talking.
Reliabilty I think depends on where you live. When we lived in Southern Louisiana, we were always dropping calls. They would blame it our phones. However, my husband and I had two different phones from two different manufacturers and yet we would both drop calls all the time. As soon as we moved to Texas, the problem stopped. Sure, we still have the occasional dropped call, but not ALL the time like before.
Overall, I am happy with AT & T as a wireless provider.