Whats the best way to access files on a Vagrant VM?

Developing code with a Vagrant VM, the repo is in the VM but I want to edit/visualize the code via my editor in the Host. I could export the VM data via NFS and mount it in the Host. My editor can then access the files as if they were local. But I'm not sure how well hg/TortoiseHG can work with a repo on a NFS mount. What other options do I have? Mutagen.io?

I seem to remember not so long ago something was posted on HN about a new tool/filesystem built for this scenario. IIRC it was taking advantage of the fact that the VM and Host are on the same disk to get better performance than NFS. But I just can't find that article again.

I know that the standard way is to have the repo in the Host, mounted in the VM via VirtualBox shared folder, but that has its own set of problems. The app running in the VM becomes very slow if it needs to access too many files via shared folder. https://www.jeffgeerling.com/blogs/jeff-geerling/vagrant-nfs-shared-folders