Sprint has pretty much always sucked, anyone can tell you that.
Verizon charges too much. But has good coverage, and locks everything off on all their phones.
AT&T is a good mix of both, with they're stupid data cap which you'll run into a LOT faster when you find out how much faster 4G is. (3G was unbearable for me, 4G is faster than my wifi)
Us Cellular has been good pricewise, coverage wise, and all else. And now they actually have good phones too.
I'd get a 4S while it's cheap, if you really must have an iPhone. iPhone 5 practically needs to be reset out of the box, which is just stupid.
Otherwise there are plenty of RELIABLE 4G Android phones like the Razr, the S3, and the One X.
Plus they're all easily rootable which will allow you to uncap 3G data speed in case you're stuck without 4G.
