I have done both, 5 leg domestic and 1 leg transatlantic for part 121 airlines and done nearly every type of flying for the military (heavies). I prefer domestic for the radio coverage and lots of places to land when stuff hits the fan. I prefer long haul for cooler/longer layovers and less landings to show off my poor landing skills. Each has good points bad points but as others have stated, I can't sleep properly on a jet nor when crossing more than 2 timezones. Having the option to choose (eventually) at AA would be nice for most people but nobody has mentioned SWA's intl push out of Hobby to begin next year. We don't know if it's only going to be "close in" destinations of 2-3hrs or maybe 6 hr legs when the 7/800 MAX's hit. They may still go to Hawaii someday as well. Will Asia or Europe ever happen at SWA, prob not but they may go like gangbusters in Central/S. America/Carribean if they see profits there. They may even do the same out of Love if the Hobby stuff works out great, who knows...Back to the OP, go with the one that hires you first, go with the one that has the closest hub (driving to work is much better than flying) second, and go with the one that you think will make you the happiest, third. If you absolutely must fly widebodies internationally, the choice has been made for you. The first 2-3 yrs at either place will be about the same QOL wise, expect reserve lines. The pay at SWA the first 3 yrs should be quite a bit better but if all things go as planned (they never do) the next 20 yrs, AA may pay more. People are talking about AA's 2018 pay scale, I REALLY hope they get it but many a beautiful contract has been yanked from the pilots before it came to total fruition. SWA currently doesn't have any "planned" pay raises (and probably won't get any 8.5 or 18% raises like AA is planned to get) but if they can get 4-5% annually for the next few years in their negotiations, that would keep their pay above everybody elses on the 737. Lots of stuff to consider, the answer will become clear in 30 yrs...best of luck!