Upgrade is a tricky topic for a SWA/JB comparison. Both upgrade times are highly dependent on growth, and a much smaller pilot group at JB can easily lead to a faster upgrade with fewer actual bodies being added. However, if the economy tanks or one or both of SWA/JB stop growing, the upgrades will stagnate rapidly. At least SWA will eventually have some retirements ramp up, but I don’t see retirement numbers on the JB overview page.

So again unless you live in NYC/BOS/FLL areas, SWA is the answer.