For what it's worth, I just did a trip to Vietnam and used the JFK/Singapore/EWR nonstops as part of that. If you can get to and from the New York area, it's absolutely worth it. My flight left on a Thursday evening out of JFK around 10:30 pm and got to Singapore on Saturday morning. I was able to get 2 good sessions of sleep (especially since it left so late), and I didn't have to fully wake up in the middle of the trip to change planes. After a short layover and 3 hour flight to Hanoi, I was able to take a quick nap, go for a food tour of Hanoi so I would walk around and have food chosen for me, and I woke up on Sunday without any jet lag! The cheap seats are premium economy, but weren't horribly more expensive than another flight where I would have had to wake up in the middle of the trip, and probably would have needed a few days to get over the 12-hour time change. The seats are similar to first-class seats (not fully lie-back like business class, but pretty comfortable). Some melatonin, ZQuil, and allergy medicine made me drowsy enough to sleep comfortable even though I was very excited about my trip (2 weeks in Vietnam and Cambodia -- wonderful!).
