Ryanair love them or hate them facts are facts they shift bucket loads of people and invariably any airport that entertains them will reap the reward. I have seen it first hand and its not only the airports that benefit but entire communities from taxi firms to hoteliers etc. I was even told by a policeman they were glad to have Ryanair as they making a fortune in parking tickets from all the extra custom at the airport.
But fair play to Man airport for standing their ground with Ryanair but equally you cant blame FR for trying to swing a deal I would.