I have never flown KE in F, but I can assure that the bibimbab and the ramen in J are very different from those served in Y. This being said, I'd love to hear from those who travel with KE more often than me whether they find KE J menus rather repetitive, heavy and possibly dull -- I think they got locked in the same Korean dishes + steak (fine meat, cooking skills may vary) + fish in heavy sauce since several years, but I don't want to be unfair to them and would love to hear from others.