IF not considering the frequent flyer program, I would take DL every time I could. In many ways, they are best in class-- friendly staff, good IRROPS handling, small touches like Biscoff cookies-- these things add up to make you feel like a valued customer. Unfortunately unless you fly enough to make Diamond, Skymiles is useless.

By the way, Southwest gives out free peanuts AND pretzels, the whole can of the beverage, and they come by asking if you want anything else. Add that to no change fees and no bag fees, and there really is a full-service experience for coach travelers (it's only missing assigned seats ).