The biggest individual difference is that bluesky makes identity independent of the hosting server (via cryptographic keys) and makes content location independent of the hosting server (via content addressing).
And these features together also enable more efficient caching and propagation in the network as well as enabling features like custom feeds and 3rd party moderation tooling which works the same independently of which server you’re on. So Bluesky can give you a better global view of the network and more efficient communication between users on many different servers in the same thread.
Ironically enough, Jack’s other favorite place Nostr (which is built as P2P with repeater nodes) is also adding moderation tooling similar to that in Bluesky (labelers making use of the content addressing and account key ID) to flag stuff