I currently have the iPhone 5s under contract. Single line, Mobile Share Value 2GB plan. My total after taxes and discounts is about $63. I can upgrade with 2 year contract for $549 or upgrade with NEXT. If I only plan to keep the phone for a year or so, what is the best deal? Or does it not really matter since I'll sell the phone when I get a new one and put it towards the new one... Trying to figure out what is best for me and my plan/situation. Thanks!