Just an additional data point: NFS does not work when you use vagrant with windows as your host OS. Things like git status when run from within the Ubuntu VM was something like 25 to 50 times slower (IIRC 7 seconds vs. 5 minutes) then when I ran it from git bash in windows.
Windows use SMB to share files and folders to the network. We can mount that shares using CIFS. There's already some data posted a huge benefit when using CIFS instead of Virtualbox Shared folder
