The third best coach in Juve's history.
Trapattoni is still number one, with 8 domestic trophies, 6 European/International trophies and only 1 lost European final. Lippi is number two, with 10 domestic, 3 European/International trophies and 4 more European finals.
Allegri is clearly 3rd. He won 11 domestic trophies, which is a record for Juve, and played in 2 CL finals.
All the other managers in Juve's history don't come even close to this trio. For example, the 4th most successful is Conte with 3 scudetti and 2 Supercoppa trophies.
It was time for goodbye, though.