The shell seats in my opinion are okay for a day flight; the extra width and legroom are appreciated versus the 3-4-3 in Y. But for something like an eastbound night flight, it would be horrid. Also, the seats are getting on in age, last couple times the padding was quite worn in my instances. The prices that AF and KLM charge for W (2-3x Y fares) have gotten quite silly when you consider the minimal improvement in experience