SQ 2 HKG-SFO does not have caviar service even though this is a 12-hour flight; but the SIN-HKG leg does serve caviar (5 hour flight, and maybe competing with CX).
The service on SQ is impeccable in F, and there are minor cost cutting (the farewell gift is gone, it seems). I have noticed a change in style to be more western and less oriental (this is also true for Cathay), and personally I like that. It does mean that sometimes the passenger must ask for something rather than it being done automatically.