The 747s are pretty poor compared to the newer products mainly because everything is now really old (in SQ
terms). Having said that, I would say the experience overall (with the food, service and so on) is still miles ahead of many other airlines.
Last year, I travelled LHR
on the A380 and flew back to LHR
on the B747. It was not a fun flight on the B747 in economy - the IFE screen was tiny, the movie selection was small, the seat was not comfortable, there was no in-seat power, and so on.