I worked in field applications in my previous job -- I lived by my cell phone & I was all over the place always, and 100% connectivity was paramount for me... I would also often need to do conference calls while travelling the highway. I tried a couple of carriers, and then tried Verizon. A few things I could tell you about Verizon:
0) Incomparable coverage -- I almost always had coverage everywhere across the country.
1) Rarely dropped any call... only intermittently driving I-5 across Camp Penalton.
2) I worked many times in an RF SHIELDED building, and I got calls ringing through the shielding.
So, for me there was no comparison. It cost more, but my butt was on the line with my connectivity, and I had to have that service -- and I have the service to this day.
Recently though, I had to go to take my dog to a remote area above Temecula in California to shelter my Dog for a trip. I could get coverage (bars) there, but I could not connect a call through. The lady running the kennel said that ATT was the only provider that worked there... So... for remote areas, maybe ATT is catching up? I've heard stories that ATT coverage is not so great everywhere, but at least in this one place it was the only option.