Min days off per month: SWA wins over CAL (15 to 12)
Scheduling flexibility: SWA wins over CAL
Financial stability: SWA wins over CAL
Upgrade time to Capt: I still think CAL would be shorter than SWA
Work rules/contract: SWA wins over CAL
Union strength: CAL has a union? Really?
Management: SWA wins over CAL, but CAL isn't that bad compared to others.
Commute: it all depends on where you live.
10 years from now... who knows. I remember when everyone wanted DAL and UAL. SWA was virtually unheard of, and folks in my squadron kinda felt pity on anyone who got hired by FedEx or UPS. 10 years later and things are different.

If you're leaving at < 1 year, you'd be getting a nice pay raise at SWA.

Good luck,
Riddler