The 4S has very good reception, although I seem to think that the replacement I got after the top button on mine broke isn't as good, but it might be my imagination. It's also erratic with not updating the signal information. I was inside a submarine today and it still showed 5 bars (yeah, right) for a while, and often when i return to an area with good signal, it takes quite a while to update. Other than that, the actual reception is pretty good.
Happy AT&T customer and addicted Speedtester in CT
AT&T iPhone 4s- Primary phone with camera disabled for work
AT&T Galaxy S7- Data-centric phone for outside of work
If you text while driving, you're an idiot. End of story.