This has been discussed before, and the consensus is that 2 adults of average western size will not be comfortable on a skycouch (if I understand correctly that you would share each couch between two people).
PE is basically what business class was a few years ago, and imho NZ's PE is a very solid product, worth the upgrade over Y.
That said, I think the question is whether to get a certain skycouch or an uncertain upgrade, but I'd still prefer PE.