Planning *A RTW in F for October to celebrate my wife's retirement.
Current itinerary is ORD-NRT-SIN-CPT-JNB-ZRH-IST-MAD-FRA-DUB-ORD.

I have two choices for the NRT-SIN leg, UA853 and SQ997. I understand from other threads that SQ F is preferable to UA, but is it worth an extra 6 hour layover in Sningapore? And if so, can we do anything with 8 hours in Singapore?