The next to last time that I flew upstairs on the KE 380, I was the only one in the back section for a flight attendant to passenger ratio of 2 to 1. Needless to say, the service was extraordinary :-)
On the more recent flight, they were considerably more passengers, but I would still vote for KE. On the other hand, the D1 flight can be delightful as well. This is one of those were not sure you can go wrong with either decision