I flew UA GF from SYD to SFO yesterday.
Thumbs up from me - service superb, food superb and the seat was very comfortable - for a near 13 hour flight, I was out for at least 9 hours of it. The purser, who I was speaking to at length in the galley, was especially friendly and welcoming.
The food & drink, and the experience as a whole, was so, so much better than my last pre-merger GF trip, which was SFO to LHR. Back then, unless you absolutely had to have the larger seat and storage, you may as well save your pennies and fly in C.
If you're on the 747 (as I was), try to avoid the middle seats. I was in 3H, and due to the angled aisles as you're in the nose section, you lose a storage area that the window seats otherwise have. It could probably do with a social area too, like VS have with their onboard bar.
Anyway, it was all good, so, on the strength of that, I upgraded my C seat to GF for my flight from IAD to GRU later on today. That's on a 777, so I'll let you know how it compares.
Regards,
Cypher