Be careful with Sprint!
Please be very careful before signing up with Sprint. I joined with Sprint when the 4S first came out. First, like you, I did my homework. I asked friends who were with Sprint about their signal and I very carefully checked their coverage maps on their website. I also thoroughly read the return policy should I have a problem.
Unfortunately, I learned the hard way that just because Sprint may have good 4G coverage it doesn't mean they have good 3G coverage. So, watch out for that when talking with friends on Sprint. Also, despite their coverage maps, Sprint speeds were absolutely terrible. TERRIBLE. There was definitely problems. It was just after the 4S launch and they were hammered in my area. Several towers around here were overloaded. They gave a 14 day "grace" period to return (watch out for restocking fees). I understand they did eventually improve the signal in my area, but this was long after I was forced to cancel with them.
THE IMPORTANT PART:
I was with Sprint for a total of 10 days just after the launch in October. I am STILL receiving bills from them and I have had countless hours of horrible, frustrating arguments with them. It has been a total nightmare. Experimenting with them has already cost me about $250 dollars. Half of that was for taxes they're refusing to return and the other half was to cover the 10 days despite them not giving me any decent service during that time. I did eventually get them to waive the restocking fees, but they currently have me turned over to collections for some other $147 that they can't explain. I had another bill for over $500 that after a good month or so of arguing I finally got them to waive. I continuously get mysterious bills from them with no explanation. They do not itemize; they just say I owe them money. Dealing with them on the phone takes hours each time and often results in hang-ups. They often tell me my problems are finally solved and this time everything is a zero balance, yet I'll get another mysterious bill from them shortly after.
So, please... I probably just have bad luck, but please be very careful before signing up with them. If you're lucky enough to get a decent signal from them and speed isn't a major concern, then their unlimited plan could be nice. But be aware you have only 14 days to decide and even if your decision is no, it could end up costing you a lot more than they let on in the beginning and you could end up in a total nightmare like I am. I sincerely hope that doesn't happen to you.
Good luck.