Both have Club suites which is the individual aisle-access seat with a door. Some people say that the 781 has slightly tighter leg space when sleeping although I haven’t noticed it myself and I am 6’1”. The 77W has a nicer, smaller forward cabin so probably edges it. Both are pressurised at 6,000ft apparently! The 77W has 1 toilet per 19 J seats whereas the 781 has 1 per 16.