I flew SFO-SYD twice last year on the UA 744's, both in biz class. Flew in the upper deck and the lower deck. Quite good, no complaints, noise reducing headsets, which really do make it easier to watch a movie or listen to music (cuts the engine noise)
PTV's, nice comfy seats. Quite good.
Had the pleasure of sitting right at the wing root on the way back, taking off heavy from SYD, you could almost see all the fuel in the wings, but as we raced down the runway, the wings slowly lifted until airborne. Nothing like a fully loaded 744!
Haven't flown economy (on the 744's) so I can't comment.