The drawn-out negotiations finally came to a conclusion in the early part of deadline day as the striker signed for a club-record fee.
That allowed Olivier Giroud to move to Chelsea and in turn Michy Batshuayi went to Dortmund.
And the new two attacking options are ready to link up with summer signing Alexandre Lacazette, which excites Ferdinand.
When Ferdinand was asked if Arsenal got a good deal for the forward, he told BT Sport: “Yes I do.
“For the last few years I have wanted him to come to the Premier League.
“He is an exciting player. He has pace, scores goals and will link up with [Henrikh] Mkhitaryan.
“I think Arsenal have done very well with attacking positions in this transfer window.”
However, fellow pundit Harry Redknapp was disappointed that the Gunners failed to bring in another defender.
He said: “Arsenal going forward, it’s fantastic some of the stuff they play. It’s all top draw.
“But they have gone to a place like Swansea and defensively they are still not strong enough.”