I like the 747 UD very much, and F on the 747 in the small exclusive cabin is also very pleasant indeed. For the UD it may be quite costly to select a seat there however unless you get free seat selection. On such a long flight, especially if it is during the day, F is simply way better than CW. The BA free F upgrade only applies to the most expensive tickets though.

The 777 CW cabin is like a big dormitory in my opinion, with no particularly exclusive seats. I always pick a 747 where I have a choice, but then again I know I can get a UD seat for free at the time of booking. I've never been unhappy with the cleanliness of a CW or F cabin on either aircraft. The WT+ on 747s is the much older seat (c2000) and I agree it isn't a great advert. The CW and F seats are much more recent however, despite the age of the planes.