I have flown AO twice, both in coach. ALC-BCN and -MAD. One flight was in a 32 year old DC9 which appeared to be falling apart, the other was in a not that old MD88, which appeared to be not too well maintained either, at least judging by factors visible from the inside. Service was none, not even one soft drink, the cabin crew was rude and unfriendly with non existant knowledge of the English language. Seat pitch was horrible.
Both flights were supposed to be IB and nobody told in advance they were to be operated by AO - I´m quite disappointed with this policy of desinformation on behalf of IB.
All in all, I have to say these two flights are the worst I ever took.
They were cheap, however; in every sense of the word.