Although I spent a few months in N.Sulawesi a couple of years ago I never actually managed to get to Bangka. I loved Lembeh and could have stayed there a lot, lot longer but I was extremely disappointed with Bunaken and agree with most of the comments above - ie fairly pretty reefs with not a lot else happening. Sure you get the odd turtle or even a shark now and then, but there is nothing really to write home about and the environmental situation is complicated to say the least. It is possibly a great example of how a marine protected area can sustain a population while not being totally destroyed, but that does not necessarily make it a great diving location. In its pristine state it could be spectacular with huge shoals of fish and pelagics, but that's just not the case and I'll definitely be trying Bangka next time as my break from muck!