[quanticle]

    ATT has provided the best service of any carrier while traveling, so I will use them.

Really? My experience with AT&T while traveling has been pretty awful. In the US, in rural areas, Verizon is better. And outside the US, Google Fi gives you international data roaming as part of the base package. One of the reasons I switched to Google Fi is because it's so much better when traveling.

[ilikehurdles]

For coverage it’s Verizon > AT&T > T-Mobile. So maybe it was awful compared to Verizon, but it can be worse. I remember a doctor friend I was hiking a mountain with (La Plata, a 14k ft peak in Colorado) who took a patient call at the very summit.

As a tmo customer I know I’m essentially off-grid in much of the country when I’m outside many metropolitan areas.

But tmo is great for traveling internationally.

[jen20]

I used Google Fi for a while, and while I'd love to use them as a primary carrier again, I can't until they choose to support add-on SIMs for watches. As a Google Fi and YoutubeTV customer, I cannot wait until I no longer have to give AT&T any money at all.

[judge2020]

The only thing with Fi is that it is T-Mobile, and you'll always be in a lower priority block of customers compared to people paying for T-Mobile directly, which mean you'll see slower traffic in congested areas at peak times (including e.g. during rush hour traffic).

[survirtual]

I've been to every state in the contingent US, most many more times than once, and spent most of my time in rural areas / wilderness. Verizon was poor during the time I had it. I forgot what triggered switching from them but I didn't last long, had to switch to ATT. I switched to ATT because my Tesla uses them and I noticed it almost always had service in remote areas when I did not. Haven't needed to switch since.

ATT has a great plan for the Americas, south America is all covered, Canada is covered, and many other places. It worked really well for me in Brazil.

That said, when I start traveling to Europe and Asia more, I may switch back to Google Fi.

For domestic use, while traveling / on the road a lot? I would rate as follows:

ATT > Google Fi > T-Mobile > Verizon

Keep in mind, if you are mostly stationary it is better to use the carrier known for good service in your fixed location.