There is of course the other option I havent seen mentioned...
One-way in Y , one-way in PE ...[:?]
That starts a whole new debate about which way you would take the upgraded cabin.[?]
If your hyped up, going on holiday etc - might not care about it too much going out & will enjoy the bigger seat/more room for night flight back. It would also be a nice surprise for the return flight, especially if you dont tell your other half

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Or , your off on holiday - PE would add to the holiday feeling, nice start etc (although your then faced with Y for the return!).
Dont have kids yet , not sure I would be willing to pay that much extra for a seat - although depends on kids ages I guess...
Havent flown PE yet - but Ive made the decision to do so, I was only booking for me and the wife (who doesnt know yet [:X]).