I've been a Sprint customer for 4+ years, and I've been very happy with them. One of the plan enhancements that I subscribe to is Unlimited Roaming for $5/mo. As long as at least half of my minutes each month are on Sprint's network, then I pay nothing extra or over for roaming. This might be something you'd be interested in if your biggest complaint re Sprint is lack of coverage in one particular (and relatively small) geographic area.

One of the reasons that I am so happy with Sprint is because I use my phone as much or more for data (email, web browsing, IM chat clients, text messaging) than I do for voice calls. Sprint has the best data network bar none, and the cheapest data plans too. I can't imagine using my Treo 650 on any other network.

There are a couple of online forums for Sprint users where you might be able to pick up lots of tips and info:

http://www.sprintusers.com

http://www.pcsintel.com