I'm a senior and have had T-mobile all through my time at Drew --
Service is an issue in some buildings, namely the Commons, McLendon, and Tolley-Brown. Definitely a problem when I lived in T/B during freshman year; I often had to go outside to make/receive phone calls, which isn't great during winter months. I really haven't had a problem with the rest of campus, though, my phone has two or three bars in most areas. For me the occasional inconvenience isn't worth switching to a more expensive provider.