This is arguable. I once flew LH from FRA to JNB in J and in the middle of the night, I decided to stretch my legs. Was a 744 and I walked into economy section and stopped next to one of the door. IN THE MIDDLE OF THE NIGHT when they have nothing to do, a flight attendant came and told me VERY rudely: "Don't stand there, you're in my way". I do not think I would have ever heard a DL FA say something like that to me. So to check, I asked a friend who works for LH and he told me: they thought you were Y passenger. They are very rude to Y passengers in general! Another friend no later than yesterday told me he tries to avoid LH because of their rudeness in Y.
Well for my part it was a single experience. On the other hand I do not like DL's international too much either, esp since their food is not great and they now charge you for alcoholic beverages.