T-Mobile

Switched from AT&T and it is much cheaper for us as a family (who use a lot of data). Best carrier for traveling out of the country with free (but slow) roaming. Nice not to have to worry about large surcharges. Biggest downside is their cell coverage isn't as good as AT&T, but not bad enough to overcome the positives.

The anti-carriers is my carrier.

With heavy data consuming kids and some recent trips outside the US, T-Mo's unlimited data plan including international data has been worth its weight in gold. Service coverage is a step down from AT&T, but paying nearly $80 / month less for family of 5 is a no brainer.

Been with T-Mobile for many years - great customer service, great coverage for int. travel

John Légère personally restored my grandfathered plan and made me an instant fan.

When they pioneered free data in Canada (even at limited rates), I became a fan. When they doubled down and made it 4G free service, I became a loyal fan.

Cheap plans, first to implement features like wifi calling, and plans cover Europe by default.