the 747 is gone on tlv route for almost 9 months... but even on the 747 dl j to cx j what are you smoking??
I agree with Ilherman. CX J on 777 is only marginally better than DL J on 777.
The seat is virtually the same and DL even has better bedding than CX, the IFE is the about the same, the service on CX J is a little better than DL.
And DL has wifi!
I'd pick DL over CX just for the wifi.