The reason(s) I do YYZ-NRT-SIN is because:
1. Gives one of the highest mileage with a shorter travel time (approx 9403mi HKG vs 9736mi NRT)
2. Like some more SQ time than 3 hours...... (with 7 hours I can complete approx 2 movies and some time on a more superior IFE system)
3. I like the Japanese meals
4. I personally find the Japanese passengers tend to keep their washrooms/surroundings cleaner. Also they are more courteous.
5. I like the NRT lounge (showers, noodles, soup) as opposed to HKG...... lounges so/so and the SQ one doesn't even have washrooms.
6. I find NRT airport is less congested than HKG
7. For AC/SQ connection, the walk @ NRT is shorter
8. I cant sit for long, so a split mid way is perfect....... (not sure why but after mid flight i start counting down the time)
9. Easier to use E-upgrades