Yellow Triumph
Both EK and SQ would be my recommendations in Business on that route, and I use both extensively. I have to say I prefer EK380 as the A/C due to the stand up bar- some where to stretch a bit, and it is quite sociable usually.
As for Dubai / Singapore re the change of planes it is down to personnel preference and Business lounges are much of a muchness, but would probably say Singapore but only just.
Have a good trip.