I actually just completed 2 F Class flights back to back
JFK-HKG (77A)
HKG-LHR (74A)

My observations:

1) The 77A seat is only slightly different (mostly cosmestic) comapre to the 74A (eg. the grill beneath the ottoman for the ventilation comes out more and it is a different material, the carpet is slightly darker in the suite area (maybe this applies to some of the newer 74A as well)
2) Different AVOD system on the 77A (with camera view outside as well as a new Airmap system)
3) The cockpit Crew Rest area is one of the issues I have ont he 77A as they sometimes bang on the door too much when they try to open and close it.
4) The ceiling height feels less airy on the 77A- prob because of the buldge that comes down in the middle (for the crew rest area)
5) I actually did not have any issues regarding noise from the Galley and the curtain blocked off the light and noise well (combined with the height of the suite walls). But the 74A is definitely quiter (even when you sit in Row 4)
6) There are no flowers at all compare to the little flower they have on each seat on the 74A. Actually they did not install a vase/holder on the wall for the window seats on the 77A
7) Toilets - as discussed above, it is just not the same as the 74A

Overall experience.

Having tested QF/BA/AA/CX in the past 3 weeks (all in F Class Long Haul international config), I must say CX is still a clear winner in all categories, including catering. I noticed some people mentioned the food on BA is better and when I tried it I find the quality and presentation is similar to what you get in CX J Class (it is just plated nicely) and CX's Snack selection is much better (both Chinese and Western).
However I guess this is just all based on personal taste, so I think it is unfair to compare other airlines jsut based on my opinion. Also the port where catering is loaded makes a huge difference (eg JFK vs YVR, where the food from NY is not as good as YVR).

The seat is definitely the best on CX (even when compared to the A380 suite on QF. It is just more spacious but still cozy and you don't need to swivel to the side to convert into a bed). The only improvement on the CX suites - I personally wish they remove the wardrobe in each suite and just increase the width of the buddy seat/ottoman area.

Service is great on both flights and I actually find the FA now can cope OK even with a full cabin (on both flights it was 100% full in F Class). I think they do get some help from a J Class purser in the galley.

Also on the LHR-HKG flight, I basically finished a 5 course dinner and tuck into my bed within 80 minutes after take off. That is pretty impressive IMO (considering it was a full cabin and at least 6 others ate at the same time + making the beds up for the 3)