I've not tried Vagrant on Windows (or indeed used Windows for a while). Is it easy.to give the VM full access to the Windows filesystem, the way that Cygwin has?
It's easy to map a directory on a Windows host to a vagrant VM. By default, Vagrant will share your project directory (the directory with the Vagrantfile) to /vagrant.
I've found network folder sharing (cifs or vboxfs) to be quite slow and buggy for certain tasks. Is there any known good alternative?