To answer your question about 3g and 4g on different carriers, i would pick Verizon's 4G LTE because it is the fastest 4g available, and there is more service available then sprints 4G. If i were you i would wait on buying a new phone and wait to all the new phones come out this year and make your choice then. There is not point about arguing about phones that are aging. Droid and Apple will come out with new phones this year so just wait.