They’ve been more reliable for me. A 737 can land in visibility that makes a rj divert. I sat in a CRJ in DEN following sim training waiting out a snow storm while SWA and United were able to depart. They aren’t frequently delayed for crew rest (this one is SkyWest fault and not the aircraft because they schedule min rest overnights and don’t have a pad if the crew gets in a little behind). When ATC starts restricting arrivals, the small rj’s are the first to get cut, while the 737 gets to go. On a recent commute I got to work because I went on SWA departing about the same time. There were thunderstorms affecting flow and all of the United 50 seat rj’s were severely delayed and I wouldn’t have made it if I relied on United. Southwest isn’t without their faults, but they’re more reliable than tired old 50 seaters when things go south.