Definitely NZ
The NZ lounge is a bit overused and worn - but benefits from lots of well designed elements and lots of glass/stone etc that looks quite modern and somehow 'natural'.
The SQ 1st lounge feels like its all the furniture they WOULD have put into a lounge 15 years ago - lots of tan leather bucket seats. Its rather a small lounge so you feel rather conspicuous.
From memory it was a rather sorry champagne/sparkling wine offering in the SQ lounge too.
But remember - you can take your boarding card and go visit both!