Just in the news: another massive black hole discovered in or near our galactic core. Not quite as big as Sagittarius A*, but massive enough to be proof of a new class.
http://www.sciencemag.org/news/2016/01/astronomers-spot-another-giant-black-hole-our-backyard
I couldn't access the paper, so I didn't see if they mention this: how does this affect the calculated mass of dark matter for the Milky Way?