I flew SQ for the first time in November SIN-NRT and was completely blown away by the service< I do believe they are the best of the best and their J seat is the best in its class in my humble opinion, I'm a big guy and I thought it was extremely comfortable, you can view my latest video report on this flight here:
http://youtu.be/kisYfMyCFyg
Again I'm sure mileage varies per person and maybe I got lucky, but both me and my wife were blown away by what we experienced.