I have flown both CX and SQ.
I have flown SQ many times from Europe to Singapore, and from Singapore to desinations in Asia. These flights have been on board B747-400, A340-300, B-777-200 and A310-300. Then onboard service is higher than "normal".
Regarding CX, and have only flown with them one time from BKK to HKG on a A340-200. The onboard service was like SQ.
I have been traveling many to overseas destination using SQ, SK, TG, BA, and AY. From a scala from 1 to 10 I would rank both SQ and CX with 10, when I comparing with the above mentioned.