I'm using Virtualbox for Linux as a guest OS, but the setup of the Guest Additions for Linux is awfully troublesome. When the guest is updated (could be daily with Ubuntu for example), it's very often the GA are damaged and require to be reinstalled. That process is unfortunately a pity for Linux, very irregular and unstable. Need to deinstall some components and reinstall them manually, with guest reboot in between.... and uncertain results, sometime it works, sometimes it just does not !
Now, I fear any updates of any kind (VirtualBox itself, the guest OS, the GA, macOS) since I know I may need hours and hours to get it working back (get the GA operational)...
Really thinking of switching to something else... unless VB improves this point !