After my recent 12h experience with Lufthansa in C I came to the conclusion that teh seat is the most important factor for me. I had a stellar crew, friendly and attentive, food was good as it gets, drink service constantly etc. But everything fades when the seat is so worn out that you feel the hard part under it and you cannot sleep. After 10minutes everything hurts and of course the angle does not help either. Additionally the IFE is outdated too that it is no fun watching movies (selection very limited anyway).

So I will choose airlines much more in terms of seating then everything else. I even will prefer american airlines when they provide lie flat seats, even if the service will be subpar.
Just my 0.02$
W