I had a 3GS on AT&T and just moved to the 4S. It's been horrible. I don't know if it is AT&T or the phone but I need to make a decision fast on what I'm going to do. On the 3GS we experienced dropped calls, but with this 4S, it's more like I can't get the phone to even call anyone!
I was in Boston over the weekend. I kept trying to call my sister who was also in Boston so I could locate her. My phone kept saying it was calling her, but I wouldn't hear a ring. Then it would say call failed. Then I got a bunch of "call failed" in a row. It lasted for a good 20 minutes. I had 3 bars on my phone. I was like WTH?! She said she was trying to call me too, but it kept going straight to my voicemail. She is on VZ with a Blackberry. I eventually got through by calling my neice, who is on VZ and has an iPhone 4. Not sure if I got lucky and finally got a call connection or what the issue was.
Now I'm back in the Albany, NY area today, and I spent 15 minutes trying to call my husband to wish him a Happy Anniversay and I couldn't get through. Tried his cell (iphone 4s too) and the land line number. Same issue where it says "calling" but I hear no ring and nothing happens. Beyond frustrating. I don't know if I should cancel and go to Verizon or what. I have heard they have better reception in my area, but the bill will be quite a bit higher. Ugh.