In business class I would recommend to go with SQ to NRT as a first choice if you can gat availability. Second choice would be NH. JAL would be my thrid choice. AA and UA last choice.
If you only want to get to Asia and not just NRT then the best routing right now would be the SFO-ICN SQ 77W flight with the new J class. However, I don't think SQ offer awards on these flights (yet). I recently flew SFO-ICN-SIN in J and it was pretty good.