even more reason to buy phones second hand and avoid contracts all together. i'm with verizon and cant really imagine switching, had at&t and it blew big time, so had to switch to verizon. Now i can actually make phone calls, at&t dropped calls couple times a day. I can count the number of dropped calls with verizon on about 3 fingers, in about a years time. Sprint is a joke around here as well.
Network quality is hit or miss. It depends on location as well as how many people are using that tower. Over where I live, AT&T has very good coverage. Equal to Verizon and certainly better than T-Mobile, my last carrier.
Sadly, with the state of cell phone prices in the USA, it makes no sense to buy/bring a second hand phone without signing a contract anyways. Unless you're with a smaller carrier like Cricket, MetroPCS, etc., you're still paying the subsidized price for cell phone coverage from Sprint, T-Mobile, Verizon, and AT&T. Those smaller carriers do charge you a subsidized price but it's more palatable than from the big four carriers. If you don't need data, there's not much you can do but if you do use a smart phone, it might be better to get something like the iPhone (even if you don't like iPhones) and sell that while going with a cheaper smart phone you get second hand.
I really wish the US would dump contract phones altogether and switch to an all-prepaid model. It's not going to happen, and I think a lot of people might disagree with me about this... but my view is that the situation that I find in other countries is much better than the situation in the US (and Canada). You choose your phone and then you shop around for a carrier and I find that their rates are cheaper and they are all vastly more competitive than in the US. Things like tethering, text messages, data caps - they are all cheaper and more negotiable. Even the phones are generally a lot cheaper.
We'd all have cheaper rates in the US (and Canada) if there were more carriers, shorter or more limited contracts, and everyone went prepaid. If you could port your number for $10 and your phone worked on any carrier, and your carrier implemented a data cap that you didn't like... you'd walk. They raise SMS/text rates, you'd walk... here in the US we are all trapped. You get a chance to walk every two years and then it's a huge hassle to move if you have a whole family...
Man, I've been saying this for a long long time. Studies have shown that the US and Canada (where phones are primarily subsidized) have the highest cell phone bills. Places where subsidized plans are practically unheard of have almost dirt cheap cell phone plans.
In the Ars Technica article that DLeRium linked to, and which I've mentioned in previous threads, Hong Kong citizens and Indians pay less than $15 for services similar to what is in a $60 plan in the USA. Even allowing for higher cost of labor and other costs in the US and Canada there is no reason why today's $60 plan can't be $30'ish unsubsidized and still make decent money for the carriers. Hell, look at their profits. AT&T in the quarter ending Dec 31 2010 earned just over $3 billion. That's not revenues, that's profits. Revenues was over $30 billion.