I second mxav8r. Pay alone at Delta tells you which airline offers the best career but one little thing I've noticed at Delta vs. the regionals is that I don't feel fatigued at work anymore. Not even on a 5 leg MD88 day in the middle of summer feels as draining as the best day at a regional.

But I probably got emotionally scarred flying 7, 9 and if you're lucky 5 leg days in a Brasilia whose packs might as well have been removed in IAH to all of the backwoods Texas and west Louisiana hotspots.