In football terms they have enjoyed unsurpassed success over their term of ownership, and at face value owe everything to the football people they employed, that said the fact they will leave (hopefully sooner rather than later) the club with absolutely zero assets is testament to their inability to build value and in doing so strengthen clubs balance sheet. Their only legacy worth any note is the development of the football academy, and even that's based at a third partys' premises!
A legacy based on rented premises and disgusting treatment of the users of the Arco Arena without which they wouldn't have got Cat 2 status.