Well, the AF Y+ offering is pretty expensive, IME. But, if you really want to fly in Y+, and are willing to pay for it, then it is an option. My reading of the various threads on it, though, suggest it isn't that special. It is a bit unclear whether this means that people are just generally underwhelmed with Y+ generally, or whether AF's product isn't up to snuff with BA, VS, or SQ.

As for KL, all I can say is that I think you are overestimating how nice Economy Comfort is. Would I pay for it? Yes. But I wouldn't necessarily choose it over a free exit row.

You haven't flown the KL 747, have you? Not fun. The wife and I travel a lot and are not the type to "ban" airlines willy-nilly (we will still fly LH Y, for God's sake), but the wife took one flight on a KL 747 and vowed to never set foot on one again.