I haven't noticed any difference in stability or performance between the two for interactive development work. I primarily virtualize Linux atop Windows, and Windows XP atop Windows (though now this is built into Windows 8) in a desktop environment, and occasionally OSX atop Linux or Windows. I switched a few years ago from VMWare to VirtualBox. What’s the difference between VMware Workstation Player and VirtualBox Compare VMware Workstation Player vs. Will restrict your ability to use their product based on third-party requests.Closed source - you're at the mercy of their engineers for bug fixes and features.Has well-established third-party development and distribution programs.

Well established and respected in the enterprise market.Xen, KVM, VMWare ESX, fall into a different category - theyre hypervisor based virtualisation stacks. The large company that backs VB is Oracle, which isn't terribly FOSS friendly. Virtualbox, VMWare Workstation/Player/Server, QEMU, User-mode-linux etc fall into one category of VM - theyre hosted within an existing OS, such as windows or linux.GPL means you need to be careful about what you add to the source if you redistribute VB.Oracle can't issue a commercial license for anything other than the USB drivers.

You get the complete VirtualBox for free.

GPL insures your continued access to the source (or likely access.Oracle has magically 'un-FOSS'ed' other FOSS products they acquired from Sun).

VMWare actively blocks installing OSX in their Windows and Linux desktop products ( edit: thanks Clarke).

Virtualbox vs vmware workstation