Wow Bandanaira is a ride in its own, It's more of a historical place than a really worth place to dive.
I've been there a long time ago, just a couple of years after the "King of Banda" Des Alwi died, he was the owner of the hotel Maulana which was the only land operation allowed to operate dives in the Banda islands, Maluku divers had been sacked out before. Hence nobody could provide diving at that time, so I just snorkeled first around the hotel for the Mandarin spot (big fatty mandarin fish, the largest I've seen, not even shy), also on the coral spots near to the volcano and off neighboring Pulau Ai where I stayed as well.
Coral was good but honestly it lacked of fish life, even though hammerheads sightings were reported around.
I met the founder guy from Blue Motion on a later trip to Ambon, he told me had started his op in Banda but it was too late for me to try. So I only know Blue Motion Ambon (now closed) but not Blue Motion Banda.
As for history it's probably one of the best places in Indonesia to stay : lots of old dutch forts, dutch cannons lying in the grass, nutmeg plantations (at Medieval times nutmeg was sold at gold price in Europe, Banda islands were kept secret but they can explain a lot of things of what happened in the western history like the discovery of America or the rise of the VOC beating portuguese vessels that could't stand the Banda SEa.). The food is also the best you can find in Indonesia, smoked fish in Kenari almond sauce, cinnamon flavored pancakes filled with pala jam.
There was one dodgy airline with small propeller planes which was operating 2 or 3 times a week from Ambon. Then they sudenly stopped because they were not paid by the regional governement (business is not easy in Maluku, ask some of the people who tried to set resorts there...) so ther was no access to Banda anymore for some years. Then there was a fast ferrey operating whenever waves (that can be terrible in the Banda Sea) allowed.
I really don't know what's the transport situation is currently.
So sorry for that long post.
To make it short : if you expect diving only, there are better places to stay, if you are a history buff this is the place in Indonesia, if you like traveling and serendipity Maluku is the region to go.