Well in the event that you are fortunate enough to get hired by one of them let alone both, here are the things to consider:
CAL offers more variety of flying with domestic and international and different airframes to fly.
SWA offers more variety in terms of domiciles.
CAL you may be able to upgrade faster. I say may because what is true now (2-3 years) is not always going to be true. That said, even if the upgrade does slow down here at CAL i think it will still be a little faster than at SWA.
You touched on retirement but I don't know enough (read anything) about SWA so that is a subject left to someone else.
As far as scheduling each are going to be a little different as well. I think on the 737 as a junior lineholder you may get more days off per month at SWA based off what I have seen posted here in the past. However at CAL the senior guys can pull 16-18 days off a month.
Reserve sucks no matter where you are. CAL you will be off reserve in 1-3 mos. Not sure what the going rate is at SWA.
Whichever way you end up going the job is going to be what YOU make of it. Anywhere you go there are going to be the people that love it and the people that ***** about it. I have been fortunate to work with some great folks at CAL and I know a couple guys in my squadron who are in the pool at SWA and are great guys too.
Contracts, pay rates and work rules change over time. Sometimes for the better, sometimes for the worse. The right choice, if you have a choice, is the one that makes the most sense to you.