This is a no-brainer IMO....but then I've been spoiled by TATL upgrades and can't imagine going back to Y (although that may well happen later this year ) so I would definitely upgrade. FWIW the fact that its a 77W wouldn't make any difference to me....on that length of flight I'd upgrade on pretty much anything!

Warning to the OP - one you experience the pointy end of the bus it's very very hard to go back