I've always avoided smaller discount airlines because, as mentioned in this article, they don't have the capacity to recover from the daily issues that can arise. I don't fly SW and don't consider them a discount carrier (their fares were always on par with the full service carriers) but they were once a reliable airline which it appears they will not be for the foreseeable future.
xhttps://www.inc.com/kelly-main/southwest-becomes-one-of-americas-least-reliable-airlines-after-one-bright-idea-backfired.html