I think it's kind of sweet as a nickname for Margaret or Mary or something along those lines. If I was a Madison (heaven forbid) I'd much rather take Maisy or Maisie as my nickname. But I don't think it's quite enough for a full name; it's a bit childish and I can't see a grown woman with it.
I also like the nicknames Mamie and Mimi. They've actually made the names Margaret and Mary grow on me further. :-)
www.qwantz.com