I haven't been happy with Sprint, but I was even more unhappy with Nextel.
Sprint still seems to lose my text messages into thin air. Calls still drop. I still hit random tiny areas of no coverage, just enough to disconnect you if you're driving.
Shouldn't be talking on the cell phone while driving anyhow!!
BTW I have had Sprint since 2000. No troubles at all. One billing error on a new phone. Called, they spoke clear English, and promptly corrected the mistake.