You have to sit in them to see -- they are minor but significant refinements of the same design (probably stemming from the date of install of the seat in the particular plane). The CX seats suffered from too much flex and the last 2 designs have made the seat much more rigid (particularly with the legrest fully raised and in partial recline). The seat padding has become softer and more comfortable with better contouring. The latest BA seat change is one that I dislike -- the headrest has become larger and more obtrusive (better when upright, worse when sleeping unless you mask it with a pillow). You know you fly too much when you can tell the difference between the same seat design on different aircraft. The CX seat is quite good though and it is interesting to see how it has evolved in the last couple of years to become better (and different from the BA seat).