FWIW I flew Southwest for the first time last year on the way to Oshkosh. Comfortable aircraft, free (salty and too damn sweet) snacks, cheapish booze on board, low end of market fares and free baggage. And for the most part great staff especially the FA’s who were a hoot. Having said that they hit us with a 6 hour delay out of Midway and that was not great but at least the FA’s on the flight really made up for it in positive attitude. Unique and quite logical boarding process as well.
I’d place them above Jetstar but below Virgin in our terms but a hell of a good way to get around the US and waaaay better than United. Kelleher certainly started the LCC juggernaut but his original baby is still a good one.(*)
(*) but in the 80’s I had the unique opportunity to fly People Express and THAT was a great LCC.