CX wins hands down. But then again, i have never tried JAL's F product before. But I did fly JFK-HKG-SIN in CX F just last week and was blown away by both the hard and soft products. Just keep in mind that for HKG-SIN ,CX usually uses those older regional aircraft so do not expect a great F product in many of these for the near 4 hour trip , unless you can get the 747. if that is not possible, try to get a plane fitted with the (now old) biz herringbone layout (not sure if new J is offered on this route).

Besides, CX F offers Shanghai Tang PJ's. Amenity-kit wise, the CX Zegna kit for men is not really industry leading and i think JAL's with shiseido products is better, from what I read.

Lastly, if you don't like CX's food options, CX has quite an impressive snack menu in both J and F (of course F trumps J, i had the hot pot rice which was amazing and finished off with egg tarts on the F class trip).