Not so familiar with vagrant on mac (though my time is coming), but having used loopback KVM's on rhel I can say that fiddling with mount options can drastically improve stability / performance (though still much slower)

e.g. tcp mounts, getting read/write blocks matched up btw/client server and sized to be digestable but big enough to move data, etc.

also, nfs is mainly only suited for 'NAS-like' operations - things like rdbms's do waay better on iscsi or eating the vdisk performance.

last I messed with macos nfsd (which has been a while), it a way happier with smaller blocksizes (e.g. 8-64k range) - modern linuces will attempt 1MB which is too much for the older 4.4BSD based code

another thing to look at is timeouts / backoffs - it's easy to kill performance by setting these things too agressively so that the system double-chokes when it gets bogged down..