Impresssions of flight classes on long flights:
Economy - I've found if I can get the right seats, these are OK. We had seats in the back on one flight on Delta (9 hours) where we had two seats to ourselves, it was OK. The plane had a 2-3-2 arrangement, sitting in the middle of 3 would be bad. Ticket around $1100.
Comfort - A bit extra leg room and seat recline. I usually pay for this as I'm pretty tall. The seats are not comfortable. Toxket usually $1500 but varies by season of course.
Premium - More leg room and more elbow room, they take one seat out so you have more lateral room, and better food if it matters. I've gotten some deals on Premium going to Europe, a ticket can be around $2200.
Delta One - I've only flown in this domestic when we were upgraded. A ticket will be over $6000. For me, not worth it internationally. We last flew going to Miami, a pretty short flight, so it was no big deal. The seats are fancy. We had one flight to Seattle in Delta One, not "first class". I spent an hour playing with my seat.
My wife thinks Air France has slipped, I think the majors are pretty much the same. I do like KLM because their FAs often are ... well, you know. We've never flown Singapore or Emirates etc. We had a short flight on Fly Dubai and the seats were awful.
