I'm sure there has been alot of improvement with the different data providers.
Back in my Electronic Systems working days in the 80s and 90s where we had to go all over the US especially in the northern parts of the states along the borders to Canada and even in AR, MS and AL and you just could not use any one other than VERIZON to get your work done... Arkansas was the worse with all of the mom and pop telephone companies there. Using their lines with our VERIZON Phones they would ask for a credit card number when you made long distance calls haha... the WALNUT RIDGE Telephone company still exists today I think...
All of the government travelers were issued VERIZON telephone cards and VERIZON Broadband AIR cards devices back then. VPN back to the home network was a must have thing back then...
Have stuck with VERIZON ever since.
We use VERIZON MIFI everywhere we go today... Even works in GOBER TX...
Roy Ken