I'm currently on AT&T w/ an iPhone 3GS and the quality is atrocious. I love the data speeds but the number of dropped calls I've been getting is a bit annoying. (Then again I lived in South Korea for the past three years.) But now I hear that Verizon and Sprint both allow their GSMs to be unlocked after a certain amount of time, which will be useful when I head back to Korea for a visit this summer. The problem is that I'm a college student and I need help deciding between Verizon or Sprint for the iPhone 4S. I get 20% off Verizon and 23% off Sprint because I work for the university. Doing the math, is saving $10 every month work not going with Verizon? My campus is blanketed in Wifi but I want a carrier that's reliable, cheap/affordable, has decent data speeds, and will expand in the future since I want to be one of those long term members.