As of May 2004 it seems that there are 3 different generations of the flat F (suite) seat deployed on different aircraft. It looks like the oldest is completely gone. Each generation has some small incremental improvements in comfort of the seat but the basic design is identical. The newer seats have better rigidity and better padding (both contouring and the type of padding used). The rigidity improvement is fairly important in some flight conditions such as turbulence while sleeping. Overall it is a very impressive seat, but the SQ seat is better and the new QF seat is also better now (due to a huge improvement on the QF side). Rather ironically the worst CX F seat that I have recently experienced was on the A346 (which I presumed to be their newest aircraft and the showpiece -- not too impressed with it, except for the cool lighting effects and the great temperature control).