The ease to change plans and the cost, cost, cost.

The ease to change plans and the perfect call quality courtesy of Tmobil for far less cash! Having a single line of cellphone to cost under $15 is a huge help to my budget and I even have international calling options if needed. Finally when I got a new NUU10 cellphone and put the Tello chip from the old too the new it simply worked. No hassles and my original Sim was available on Amazon to get me started.

Genuinely helpful customer support

Customer service is prompt, and unfailingly polite and helpful. The "worst" experience I ever had over several years was simply calling at a time/day when I couldn't immediately connect with an agent and so got voicemail instead. Every other time, they sorted out my issue/misunderstanding/whatever with no fuss. It's a serious relief to know that customer support isn't going to be a waste of time, stressful, or fail to resolve problems.

Never any problems with coverage

Never any problems with coverage, calls clear and never cut out, and an unbeatable price. International roaming can get expensive but that happens with any carrier.