Minus the fact that TS's company is paying for his(I would go with HND for this since all paid)..
Gonna see flight timing and price difference..
Like for now i'm checking Oct tickets, looking at redeye flight..
To NRT on SQ would be about $1.5k plus abit for 2 pax while ANA with pretty similar timing would cost me $1308/2 pax..So for this case, ANA would be my choice..
HND wise if i take SQ 8am depart SIN and return at 5+pm flight from HND, would cost me $1390/2 pax..Not forgetting i only reach in the noon..And have to wake myself up in the wee hours to go Changi..
So in short, have to see individual flight preference..