WHile Verizon and ATT are Ford vs Chevy each has undivided loyalty.
What should also be considered is external antennas to amplify the signals. I installed the Weeboost RV Drive X which is a Staple in the trucking industry for better mobile connectivity.
That alone dramatically improved my 4G reception and i found it invaluable. We stayed at a campground in the Cascade Mountains it was in a deep valley with No reception, the Campground Management said there was NO way we could get cell service withing 20 miles of the Campground. I turned on the Weboost and wa-la we were able to at least make calls, all the other campers were baffled seeing us on our phones when they could not get a single bar.
So you need to add to the discussion External antennas for reception reliability. Note I tried the Winegard 4G antenna it was total crap the Weboost was 10 folds better.