Xen Project is a hypervisor using a microkernel design, providing services that allow multiple computer operating systems to execute on the same computer hardware concurrently. Developed by Citrix
License: Open Source
Xen is an open-source hypervisor known for its flexibility and efficiency, making it suitable for a range of systems, while VMware vSphere Hypervisor offers robust enterprise features and strong integration with VMware's ecosystem but comes at a cost. The choice between them often depends on the specific needs for customization versus comprehensive enterprise support.