This is what I found as a tonewood:
As a tonewood, Bubinga has also been called African Rosewood which is a fair description of the tone although it is not yet used very extensively due to the difficulties faced with bending it.
Stephen Kinnaird is a big fan and says :"I have a growing appreciation for Bubinga. Visually it can be quite stunning, with deep curl, Pomelle figure, bees' wing mottle, etc. Even the plainer versions when well quartered are attractive.
The pinkish mauve color is off-putting to some, though I find it attractive. It is hard, heavy and dense. The interlocking grain, which makes the wood so attractive, also make for an exciting time at the bending iron. This wood can resist you with a stubborn determination. A good night's sleep is essential before bending.
The sound is so close to rosewood, that Bubinga well earns its nickname of "African Rosewood". That overtone structure one hears with rosewood is equally present in Bubinga, and yet at a reduced price tag. If one wanted a guitar with a traditional sound, but with more visual drama than Indian rosewood, Bubinga should definitely be considered."
Subjective tone...
I would classify this wood as providing a slightly dark and woody overtone content with a low to mid end predominance- much like Indian Rosewood!