Unlike Jennifer, my TJs tortillas lasted at least 8 days - I just ate my last Roast Beef-Cheddar-Cream Cheese wrap after crossing the Arctic Circle (southbound) this morning. Now, I did keep them in soft cooler for 3 days. Then in airplane luggage on 3 flights for 4,000 miles (it's cool at 33,000 feet), then in the rental-car trunk from Fairbanks to the Brooks Range. Then in my pack for two days (also in Gates of the Arctic).
Edited to add: I'm now home, and the TJ tortillas have gone another 300 miles by road, spent a day in Fairbanks, two more flights, and a night in the hallway before I unpacked. And are still fine.
YMMV. Based on your climate.
But based on the above info, I'd go with the Mission ones in the future.