Bunya is an Australian wood so the Australian manufacturers such as Maton and Cole Clark use it. Its a brightish sounding wood something like Spruce or Maple. Its not mellow like Mahogany. Some will say rightly that its more about how the instrument is built but that's my two bobs worth.
I like the NEW Maton ukulele's. The older Matons were sweet but a little overbuilt. Recently they changed and are MUCH more lively. As to the Bunya top model? I'm not sure. I haven't played one.