My opinion as an outsider:

I also had offers at SWA, DL, Allegiant, Breeze and Avelo. Im coming to SWA. The negative commentors all seem to jthrough out the earnings difference right away. And if your goal in life is to see how much money you can amass, the sure, go with Delta. However, I would argue that is pretty short sighted and ignores the fact that even at SWA you will make more than the vast majority of the American public. Yes, I feel im worth that, as I put in a lot of time and hard work to get here and as pilots we assume a large amount of risk and responsability (thats why I will support the union and will happily strike day one on the line if it comes to it). Having said that, SWA offered the best shcedule flexability, job stability and pay in a location where I want to be without commuting for the rest of my life (which would severly diminish QOL even with better work rules). That and I am confident that we will get a good contract in the relatively near future that will be more than enough to provide a very comfortable life for my family and fairly compensate me for my experience and expertise. I also felt a very stuffy, corperate culture at Delta that I just didnt fit in with. I have friends there, but most of them honestly arent REALLY there as they are on Mil leave for reserves more than they are at Delta. So their experiences are very different (commuting a few times every 6 months is a far cry from doing it weekly).

Go with the airline that offers the best combination of elements important to you. Its unlikely that any one airline will hit ALL of your requirements exactly, and they all have their own plusses and minuses. For me it was between Avelo and SWA. No union at Avelo and future uncertainty were the deal breakers and why I chose SWA in the end (Breeze isnt where I want to be, Allegiant is a hot mess with terrible pay and rules and Delta isnt where I want to be and didnt feel like a good fit...yes it matters).

Just my $.02 as someone getting ready to start.