I've been on LY's 777 twice. once from JFK and once from LHR.
I really enjoyed it is cleaner and better kept than the 744.
CO's coach on a 777 was also neat when I flew to EWR, the only difference between LY's coach on a 777 than CO's coach on a 777 is that CO has an interactive menu and LY does not, But I highly reccomend both.