Mariner, who scored nearly 100 league goals for Ipswich during eight years at the club between 1976 and 1984, said: "It is absolutely one of the best jobs in the country. There will not be a better opportunity outside of the top flight.
"The new owners want to take the club places. I would think that the club already have a top-three finish in mind.
"There will be money to spend and you need a couple of players in your squad who are difference makers at that level. Whether that's a striker or a defender there are a few who can turn draws into wins.
"It's all about squad depth now, be it at the top of the Premier League or the top of the Championship."