Even as an ATL native, I've been very happy earning in MileagePlan as MVPG this year after defecting from SkyMiles. This year I've had ~30k on DL, ~25k on AS, and ~8k on AA. I've used AS for 5/7 TCON flights (through SEA and PDX) and was able to upgrade all 5 using GG Certs at booking (all with only a 0-10% fare premium over lowest coach). As for my DL and AA flights, all were as pleasant as can be expected... MCE does help on AA, as does Exit Row on DL. I've paid for EC on DL the 2 times I was on TCONs, but did so at the DL Silver Medallion discount before switching the PNR over to my AS account (this trick will disappear in 2015).

Even if it weren't for the added comfort of AS on TCONs I still would have stuck with MileagePlan in 2014 for the ability to shop between AA and DL based solely on price. In 2015, though, I'll be flying every possible mile on AA given the DL earnings devaluation (hopefully enough to flip my 2014 DL/AA ratio of almost 4:1).

I've yet to redeem any AS miles but I expect to do so mostly on AA and DL domestic saver tickets in the near-term (4 young kids eliminate any international leisure travel plans for awhile). Luckily I still earn ~80k/year in my SkyMiles account from my SunTrust Delta Debit Card for instances where saver seats aren't available.