straight talk wireless at wally world

My wife has the same as yours. I am still on AT&T. We go out to New Mexico near the Az border and her phone is the only thing working where we camp. On the interstates, they are equal, some dead spots on both. In every city we've been to, they both work. Straight talk costs less, and I would switch if they'd allow me to 'tether' my computer to the IPhone the way my ATT IPhone does (with paid data, though).