They're all doing something major that violates Net Neutrality.
Sprint's compresses images and throttles video https://www.google.com/webhp?sourceid=chrome-instant&ion=1&e... They just don't advertise compression/throttling as a "feature", so it doesn't get the publicity. Sprint also does zero-rating for music.
AT&T has "Sponsored Data" and throttles 'unlimited' plans, and Verizon has their ad-tracking-injection mess.
Whoever I pay is going to get money for "pulling bullshit". I love the idea of voting with your dollar, but all of the major cell networks are anti-Net-Neutrality in multiple ways, so the whole thing is almost a false choice.