When comparing VirtualBox vs Parallels Desktop, the Slant community recommends VirtualBox for most people. In the question“What is the best VM applications for Mac?” VirtualBox is ranked 1st while Parallels Desktop is ranked 3rd. The most important reason people chose VirtualBox is:
VirtualBox is available for free with source code available [here](https://www.virtualbox.org/browser/vbox/trunk). A "VirtualBox Extension Pack" that includes virtual USB 2.0, VirtualBox RDP & PXE boot support is available only under a commercial license.
Ranked in these QuestionsQuestion Ranking
Pro Free and mostly open source
VirtualBox is available for free with source code available here. A "VirtualBox Extension Pack" that includes virtual USB 2.0, VirtualBox RDP & PXE boot support is available only under a commercial license.
Pro Easy to use
Parallels has an easy to learn and use UI. All important features are wizard based. It requires only a few clicks for the wizard to download and set up the latest Chrome OS, Windows or Linux build.
Pro Can run Windows apps as native OS X apps
Parallels has a "Coherence View" mode that allows running Windows applications as if they were native OS X apps. In this mode Windows is virtualized in background and Windows features like Jump Lists, Taskbar, Start Menu, etc can be embedded directly within OS X.
Pro Best-in-class gaming performance
Compared to other VMs, Parallels has the best gaming performance. Still, a good framerate can only be achieved with games that have very low resource requirements. A much better option for resource intensive games is dual booting Windows (via Boot Camp).
Pro Best integration ever
Con Inferior performance
Apart from second-class performance in virtualization, there are some visual glitches with Windows 8.1 on Mavericks.
Con Confusing interface and lacking usability features
VirtualBox might be a bit confusing for beginners - it requires an understanding of a lot more technical details than other VMs.
Con Very expensive
Parallels upgrades are very expensive. Even if I bough several versions of Parallels I will switch back to free VirtualBox as they even "invented" the Pro version - mainly doubled the price you have to pay each year to have the software updated.
Con Requires buying a new version of the software with each new OS X release
Chances are that the same version of Parallels won't work with different OS X releases, requiring a separate purchase of Parallels for each OS X version.
Con Home edition doesn't work with Vagrant or Docker Machine
Make sure you purchase the Pro edition (the subscription) if you need command-line access to the hypervisor.
Con Can't import OVA files
OVA files are useful because they include all of its supporting files. Unfortunately, Parallels doesn't support these useful files.
Con Can't export OVA files
One you use parallel you get trapped into a proprietary format.
Can't share disk blocks on two unrelated virtual machines (KSM for disk) too.