Yes I have flown quite a few times now on A350s, including with Cathay, Qatar, Iberia and Finnair. BA is taking the 1000 version with a new seat, so you are right to say there is a significant difference. The A350 has one big disadvantage, namely that the arrangement makes it difficult to avoid a dorm effect, whereas the 787 has smaller cabins at the Club World level. BA's A350 will have a small CW cabin, however, but it is to the rear of the main CW cabin. The 350 is slightly quieter and a better ride than the 787 but in a way the big gap is between the 787 + 350 + 380 and all the legacy aircrafts that I have to fly, notably the 777, 767 and 757 aircrafts. Within the modern aircraft the differences are quite small in comparison.