Let me share my experiences on BA and CX. I once was very hesitant of flying CX Y as I am used to BA WT. Earlier this month I had no choice but to do CX343 HKG-LGW and I was very impressed with it.
1. As it is an A350 it felt very fresh and new. Even though I booked in the day of departure, as an OWE I got an exit row all by myself. Doubt this will happen on BA
2. IFE has a lot of content, like much more than BA's highlife entertainment
3. Status really come into play. I was offered a bottle of Evian water and greeted by a CC, addressing by my surname and asked to find her for help etc.
4. I was VERY HAPPY to have first choice on meals. Don't know about breakfast as I was sleeping then. I was served dinner even before SPMLs. Because of this I was able to sleep early. I heard the food is not good (and experiences it first hand) in J but it was actually not bad. For breakfast, just after I woke up a CC walked past collecting trays and asked if I wanted to eat. I just love the proactive service there.
5. They have snacks, which is awesome. They have fruits, peanuts, even noodles. Unlike this British airline who though there is no need for these things
6. LGW arrivals is very fast to go through. No queue by the time I arrived and CX do priority bag tagging very well and bag was in the by as j arrive.d