OZ F and NH F are both solid options and you won't go wrong with either. However on OZ F you'd want to fly either the A380 from LAX or the suites from JFK.

I flew both on the same trip (JFK - ICN - NRT on the outbound from the US and NRT - IAD on the return to the US) and I think NH F won by a hair (and that's with NRT - IAD being NH old F). It was more refined IMO though again both were top notch experiences.

Something to consider, the normal JFK - ICN - NRT routing puts you on an A321 (if you do a same day connection at ICN) and that was not a good flight to be on after a 14 hour flight from JFK (crappy domestic F style seats), whereas any NH F flight will end at NRT without needing to connect further.

Haven't flown SQ (in any class) so I can't compare either NH or OZ to that. Note that you get a 15% mileage discount if booking via KrisFlyer online