I'll throw my 2 cents in... I'm just starting out a high-travel career (worked at a Fortune 500 with a super-low-overhead philosophy; became a WebEx frequent flier...) and "shopped around" a bit over the last year, trying out different airlines to see what the service level was and comparing the possibilities.

Hand down, Delta takes care of me. I don't even have status (yet) and whenever I ask for anything reasonable, I get it. Waived rebooking fees to jump on an earlier flight? No problem. Free breakfast when my 7am is delayed to 7:30am? Check. There were times on other airlines I was delayed 4-5hours for a TATL and got nothing except a cup of water. FAs that make sure I make my connections even when my flight is late (with ample "they won't hold the plane just for you, so run!" warning).

Plus, unlike other airlines (including one that claims to be so much frendlier because they are employee owned...) I believe that Delta's employees genuine care about my flying experiance and will do whatever is necessary for me to have a positive Delta experiance.

Now, the next time it takes an hour to de-ice a plane, I might not be so chipper, but... it could be worse.