Hi npet,
I was perusing the forums and noticed there wasn't a reply here yet.
For all intensive purposes Buzzsaw and Streamline are the same; Streamline is simply the marketing name given for it, for Manufacturing customers.
Once upon a time Buzzsaw and Streamline were two separate applications with two different interfaces; as they performed similar functions, Autodesk rolled Streamline onto the Buzzsaw (ProjectPoint) platform. Also there used to be the ability to "stream" live 3D manufacturing models (hence the name), but as few companies were taking advantage of it and it was very expensive, that was dropped awhile back.
Hope that helps!
Steve Williams
Autodesk, Inc.