Would confirm my feelings are that Delta best of a bad bunch, last time I flew with them was this last spring. I was treated to some very old metal (not CC) and some big storms, and they performed ok but nothing special but planes were "tired". I always use LH for the crossing just because connections through Frankfurt are better for me than LHR, and also use them for visits to the "Stans" and Eastern Europe, so keeps the old loyalty card topped up. Going further East always SQ or EK.