Flight to Europe on PEY was I would say OK. As previously highlighted by other posters, it is mainly about the space, the rest is probably not worth the additional money.
The food is exactly the same as economy. Yes there is champagne but you have to ask for it. It was not on the trolley nor was offered to me. The service is of course SQ good but still the same as Y.
As for the seat, you get more space but the width is actually not very different from Y. The leg-rest is small and kind of useless. The recline is OK, not more.
My point is that it certainly a plus over Y and worth a few hundreds dollars more but I wouldn't make 100% premium for such product, which is the price on many long haul destinations. If you can, use miles in C, it's definitely more worth it.