What are your long-term career goals? How important are flight benefits to you? Will you have to commute if you work for SA? Can you live on 1st year FO pay?

You're the only person who can make this decision, because only you know what you want out of life. If you're looking for specific information on what schedules are like at a regional or what the flight benefits are like or how difficult commuting is, then ask those questions.