I use T-mobile mainly because of their low international charges (20 cents a min in covered countries) and free text and data roaming with their Simple Choice Plan at $50 a month. I also like that you don’t have to sign a contract.
The phone carrier just came out with a North American Simple Choice plan where you can get free calling and texting in Mexico and Canada for the same $50 a month. This feature is not automatic like I thought, instead you must call T-mobile to be switched to this plan and it can go into affect immediately.
On a side note, did you know that you can text in-flight with T-mobile at no extra charge? Make sure you phone is compatible to do this and follow these steps to enable this feature.