Which wireless carrier provides the best buying experience?

There are a lot of reasons to choose one wireless carrier over another, including price, network quality, and free extras, such as T-Mobile's Binge On video streaming service. But one factor you may not have considered is the quality of service carriers deliver when customers buy new phones or try to find the best service plans.
J.D. Power tracks consumer satisfaction across dozens of industries, and it surveyed nearly 7,500 people who bought a phone from a major carrier this year.&nb