Maybe it has something to do with my location, but my experience has been that SWA is normally much cheaper than other airlines. I recently cut 70% off a trip I'm planning in May by switching from Delta to SWA. That's probably a uniquely extreme case, but I'll happily risk a delay of even a day or two if it saves me litterally thousands of dollars.

Southwest’s base fares suck, but their discount tier fares combined with frequent sales, the companion pass, and a decent frequent flyer program make them pretty competitive in my experience. That said, if you don’t live or travel on one of their major routes, they are a bad choice.