I can, and others can tell you their experience based on what they see in their areas, but it may depedn on where you're from.
Case in point: Years ago, I lived in the New Orleans area and there was no doubt at the time, Sprint had the best coverage. Cingular was good (actually, it was Bell South Mobility at the time) but Sprint had them beat. I now live in Baton Rouge, only about an hour away and while Sprint is good if you're in the city, get on the outskirts of the city and your out of luck. Cingular is good if you're standing outside and not in a building (I think it has to do with their GSM technology)but try to use your phone inside, and you're screwed. Verizon (who I'm with now) is by far the best network in my area.
And while I'm on it, they have the absolute best customer service! I've been blatantly lied to by Cingular and when I caught them on it, they acted like "too bad....we got you by the balls". Sprint was not far behind that in their 'don't care about the customer' attitude. But Verizon has never failed to help me out if I had an issue. Now, at least in this area, you pay more for Verizon, but like the old saying goes 'you get what you pay for.
I'd suggest that you pick one and try it and run it through it's paces for the first 15 days. Most networks have a 2 week return policy. But check on that to make sure and get it in writing. cingular would tell you they do and then refuse to take it back if/when you want to return it.