I have had tons of problems with the service of my phones. We use Tmobile and get NO service at our house. Although the fix for it is they now have Hotspot @ Home and it allows you to use your Wifi to get service on your phone. Its really cool and works great and is cheap ($10/mth for the entire acct). Just make sure you get a good phone cause it makes a world of difference. I bought a Katalyst for my wife and I am using a crappy Nokia and her phone is great but mine sucks fat ballz. I am currently looking for another Katalyst to replace my phone. You can also connect to any Wifi signal and get service with the Hotspot deal. The best part about it though is that any call made on a Wifi signal is FREE. That alone is worth it to me so its kinda hard to switch but I just have to find me a Wifi calling Enabled phone that works for me, lol.
I have never had ATT so I dont know how their service or anything is.