Portable-VirtualBox is a free and open source software tool that lets you run any operating system from a usb stick without separate installation. Developed by Runar Buvik
License: Open Source
Citrix XenServer is designed for enterprise-level virtualization with robust features, scalability, and management tools, making it suitable for large organizations. In contrast, Portable VirtualBox is a lightweight and easy-to-use virtualization solution ideal for testing and development, but it lacks the advanced features and performance of XenServer.