Bealine
Amadeus cutover by BA was not such a disaster considering the fact that it was a global simultAenous cutover and not a phased one. From what I understand things went much worse with US Air when they cutover to Sabre!.
And yes, Amadeus is indeed quite friendly to the users having interacted quite a lot with its users as well as some of its competitors.
www.checkmytrip.com is useful for the passengers (if they have an amadeus pnr).