I just realized that MintSim is not good if you are constantly on the move. I got my first dose of reality between paying premium for main carrier and alternative like MintSim. We just did a 3 week road trip from Southern California to Washington then to Canada (Alberta, BC and Calgary) then back to Minnesota, North Dakota, Wisconsin, Iowa, Nebraska, Colorado, Utah then back to San Diego. We are with a group of people some of them with AT&T, Verizon, T-Mobile and other with pre-paid service. Those in our group with service using the carrier's above always have full service with 4G/LTE data on every stop that we have. Those with pre-paid including Mint lost data on some of the area we stopped.
Mint and other pre-paid does not usually allow roaming inside US. Mint allows option for international roaming but this is only true for cell and SMS. I can't access data when I was in Canada which makes it very inconvenient to travel as I rely on data for maps and searching where to go.
I also noticed that I have to constantly re-start my LG-G5 and my wife's iPhone7 when we move from 1 place to another (mostly 1 state to another) in order for me to connect to T-Mobile tower else, I will get a Non-USIM or my wife will get the Invalid SIM error message.
If you just stay in 1 state most of the time and you have Mint coverage in your area then this is still a good option for you so you can save money. You just have to remember that when you travel to another place that you may not have coverage. It is best that you buy a SIM kit locally when you travel internationally than paying the international roaming option by Mint.
I am writing this in hope that Mint will make this clear on their site and eventually improve their service to allow roaming.