The focus of this article, as it was in our VMware and Parallels comparison, will be on running Windows 7 and Windows 8 guests on an OS X host, but VirtualBox’s cross-platform nature means that many of the observations made in this article will also apply to VirtualBox running on Windows and Linux hosts. One of the only differences is that OS X virtual machines, which are still labeled as an experimental feature in the current version of the software, are officially supported only within OS X hosts, both because of Apple’s licensing stipulations and because OS X won’t run on all of the CPUs that Windows and Linux can use.