Having recently lost my CX Y virginity (on a code share where I did earn miles), I would never consider them with the objective of sacrificing miles for potential in-flight experience. The one airline where I'd consider that is SQ, where I've been served Y meals superior to AA's C meals. I found CX to be very middle or the road and somewhat frumpy — practically designed seats, friendly and efficient crew who made a point of recognizing OW status, but mediocre food and drink (and no hard liquor options at all, if that is of interest).