Is Corp. gig long term. Will you be typed, do you want to stay corporate? Do you like the 121 world now. How will QOL be at corp. gig. (days off, duties not related to flying, etc.)
Will the corp. job give you a severance package (in writing) in case things go bad. Personally I would be looking at the corp. job simply because once you go corporate you are in the club and finding other corp. jobs becomes easier.
It is a question of do you want to fly a 737 for 4-8 legs a day until age 65 (Yes I am against it but it will probable happen) or fly for a corporation. Two different styles of life, you need to decide.
P.S. what types of retirement is being offered by the corporate job. SWA only has a 401K, as far as I know there is no defined benefit plan.