I've flown the A340 in F from SFO to HKG as well as the 747 from LAX to HKG a few times and I totally agree that the 747 experience is much better than the A340.

The biggest difference IMO, is that there is less foot traffic going past you on the 747 F whereas on the A340 the crew, both from F and C cabins, seem to walk up and down the aisle all the time. Also, I've noticed that sometime the crew would talk quite loudly when they are in the forward galley on the A340.