There are two schools of thought re: MAN.
An industry perspective, which is that it over performs relative to the immediate catchment. Something like 75% of the passenger throughput comes from outside Greater Manchester. The competitive battle lines are with the airports that also serve markets that the 75% originates from; mainly LPL, LBA, DSA and BHX. There are roughly 8m of the passengers a year using these airports that could use MAN and at least another 10m using MAN that would happily consider using one of others. The numbers at stake are huge and it requires an ongoing rear-guard action to protect what MAN has and to claw back passengers.
The second perspective, which I hear more from folks inside Gtr Manch but who are outside of the industry, is that it under-performs. Most comments in this regard focus on a (perceived) under performance in long haul services and as such, they believe the competitive battle lines are with London, and Heathrow in particular. Often they seem to conflate this issue with broader North vs. South issues and believe MAN should be managed in a way that showcases the fact there is life outside of London.
The management of the airport and the airport group and their external investors are firmly in the first camp. Passionate supporters of the 2nd view mis-interpret this as everything from incompetence to ambivalence, yet the reality is that the management are following the most logical commercial strategy for the challenges and risks they face. In pursuit of that, they are well regarded and well know in the industry - which is the core audience for business development, trade support and the other B2B marketing activity. B2C marketing, as with all airports, is not core simply because the general public don't react or engage with it that well. I know many airports that are trying to make social media work for them, with mixed success.