You will find it hard to get somebody who flew extended hours on a Scarebus and in a Bobby.
I am quiete happy with the fly by wire technology in the B777. I did A330 SIM in our center and I never felt comfortable when I wanted to fly basic. But again: I did not get a proper training in any Airbus. But from the A300 to the A330/340 you will be comfortable as you are used to Airbus terminology. If you go to B777 then you are happy with the conventional feature what Mr. Boeing puts in there.
Our company did both within the last few years: Took Pilots of the A300 to the A330 and to the B777. Both took the best out of it but most of them call themself lucky if the get moved to the B777. That would tell me something.
Fly safe and land happy
NG