I want my phone to work *everywhere*. I understand that it can't/won't work everywhere; but I want it to be able to. Being with Verizon, my iPhone 6 works a lot more places than it would if I stuck a T-Mobile SIM in it right now. If I don't want to be reachable, I'll turn my phone off. I am plenty capable of controlling my reachability. I don't need/want my carrier to do that for me.
what has been discussed here reminds me of a truth that is obvious, but i needed to live out this past few months: one needs to choose the network that best fits their usage patterns (location, location, location) and needs.
in september, i moved to Verizon thinking i would get better service than AT&T, which i used for 8 years prior. after suffering with Verizon for two months, i found that sadly, for my needs (which includes Caltrain where there were several stretches where Verizon has and confirmed they have no data coverage in spite of what their maps say), Verizon was not as great as i thought it would be.
in the end, i ate the ETF and am back at AT&T even after having lost my grandfathered plan.
i did a lot of spying and talking to fellow passengers on the train of different phones during my failed experiment with Verizon: Tmobile and Sprint also has holes in their coverage in many places i frequent including Caltrain.
i do believe Verizon, based on conversation and my wife's experiences moving around a lot, is probably the best overall for voice coverage. but for data, at least where i live, work, and travel, AT&T has them beat by a long shot. (LTE basically wherever i go, and responsive LTE as opposed to the sluggish LTE i was getting from Verizon in more locations than i was expecting)
i am happy Tmobile is putting on the pressure, and i hope competition continues to help out the customers of all the carriers.