It's been a well-known fact that using native VirtualBox or VMWare shared folders is a terrible idea if you're developing a Drupal site (or some other site that uses thousands of files in hundreds of folders).
Drupal 8's expanded and broadly-used Entity API extends even to Contact Forms, and recently I needed to create a contact form programmatically as part of Honeypot's test suite.
In support of my mission to make local development easier and faster, I've released boxes for four of the most popular Linux distributions I use and see used for Drupal sites: CentOS 6/7 and Ubuntu 12.04/14.04.
I recently ran into an issue where drush vset was not setting a string variable (in this case, a time period that would be used in strtotime()) correctly: