I'll describe it as Delta empowering employees to go beyond the contract of carriage minimum to improve the customer experience, and a fairly high percentage of employees do use this power for good purposes. I also tend to judge a company on how well they perform when things don't go as scheduled, and I've had largely positive interactions with Delta in those times.

Southwest is great at finding pleasant and enthusiastic employees, but also has their share of weaknesses. My experience with them for IRROPS recovery hasn't been great and I think until fairly recently, they kept IT costs contained by running their reservation and scheduling off a Commodore Vic 20. (It's the only explanation I can come up with when they would have months on end when they wouldn't sell a round trip plane ticket from Pensacola to some obscure place like San Francisco.)