Thoughts so far...
DL CRC in PHL was modest, nothing overly special. No free wifi? Bummer.
DL 579 pushed back on time, got into ATL early. I liked the choice of 3 snacks in Y, since I like peanut butter crackers. Drink cups in Y also seemed pretty decently sized. Noticed they put the armrests between Y seats UP by default which was an interesting change. Other than that, it was an uneventful flight, not a particularly new/upgraded/spiffy plane.
ATL was fogged in. And that's where it got interesting. More later.