The HFS+ problems would not be related to VirtualBox. VirtualBox gets a bad press from the Linux kernel mods too.

Apple introduced a new virtualisation framework in Yosemite, hence the rereleases of the most widely used virtualization items (Parallels and Fusion).

Sounds post hoc. The virtualization products tend to be on regular, frequent release cycles. (I know one of the Fusion product manager.)

Hell no. Vmware.