BA is definitely my favourite for First. I think CX is very close, but I don't like their cabin layout - it's all fairly subjective though.
I am surprised that you think the CX amenity kit was the best. I think the BA BAg has a far more interesting set of products, plus the case itself is worth keeping. Oh, and the contents are not soley British, they change frequently and tend to be a selection of the hotest cosmetic items from around the world, like just recently the Aesop range made in Melbourne Australia, as well as items from around Europe and the U.S.
I've got an AA flight in first this week DFW-LGW, just found out that on the day of my flight they are switching the 777 flagship suite config for a 767

. The suite was the one thing I think AA could truly call first class. Oh well, at least the DVD inflight theatre on the 767 is vastly superior to the 777's selection of entertainment options.