Oracle VirtualBox is a powerful x86 and AMD64/Intel64 virtualization product for enterprise and home use. VirtualBox is an extremely feature rich, high performance product for enterprise customers. It is freely available as Open Source Software under the terms of the GNU General Public License (GPL) version 2.
VirtualBox runs on Windows, Linux, Macintosh and Solaris hosts and supports a large number of guest operating systems.
VirtualBox is being actively developed with frequent releases and has an ever growing list of features, supported guest operating systems and platforms it runs on.
Proxmox VE is a virtualization management solution for servers. You can virtualize the most demanding application workloads running on Linux and Windows Servers.
It is based on the leading Kernel-based Virtual Machine (KVM) hypervisor and OpenVZ.