Flown both.
QR J is very similar to CX J. I like the CX seat better because the QR seat has a fixed table taking up space above your knees and restrikting the space for the legs. Food can be hit and miss on both.
CX F is in a different league. 3 seats across in a 777, very wide (good enough for 3 people to have dinner in one seat, two on the seat and one on the footrest). Very spacious, comfortable. Also there are only 6 seats, the cabin is usually very quiet.
Assuming you depart from LHR you can easily get 8 hours of uninterrupted sleep in CX F, vs. changing planes in the middle.
If it is in your price (miles) range CX F by a wide margin, then CX J next and QR J last.