Hi Zeke
Despite living here I haven't been out with the chaps at Scuba Bula but several of my customers have. I am told they are very professional and well equipped but this is reported by Open Water Students rather than hard core divers. I have definitely heard nothing to the contrary.
The resort they work with, Seashell at Momi, doesn't come quite so well recommended. But is probably adequate.
What I would say is that the diving there doesn't represent the best of Fiji, although is probably pretty good.
If you are planning on spending some cash, why not look at a liveaboard with Naia or Peter Hughes?
Maybe consider splitting your trip between 2 locations if you have the time. My favourite dives are in the North, specifically Namena and the Somosomo straight. These sites can be dived from either Savusavu or Taveuni. Both these locations require an internal flight so that limits you a bit.
Anyway, if you want more info on these or any Fiji locations, let me know.
Cheers
Greg