CX's 34C and 34S both have the First sleeper layouts. 34C means that that aircraft also has the new Business Class seats.
Some people hate the A340s. Maybe it's because you don't get the cubby feel from the nose of a 747, but I like the A340 for its smooth and quiet flight.
Service is tops as usual. No complaints there - except the flight will seem kinda long due to the stop in both directions at ANC in the summer.