Good to have you back Macaron95 after so many years of silence . I remember your contributions in the Accor forum.
On top of the seat, W class comes with some SkyPriority benefits, so it could be interesting for you. The additional space and amenities are also appreciable (water bottles, amenity kit).
For the seat : in the AF B777, W is good if you don't want to sleep, so OK going to the US but not really on the way back.The experience is better in the B787 and A350.
Cabin noise, the A350 and B787 are definitely better than the B777.
AF seems to have improved the W meal recently (it was the same as Y before).
On DL, the soft W product was better than AF before Covid, but the last reports I read show that there has been a downgrade in the service. Some other posters may give a better opinion than me, as I have no experience on DL W product.
Please note that aircraft changes are quite frequent, so if you book now, there is no guarantee that the plane type will not change until april 23.