Quote from linux-kvm.org: "KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko. KVM also requires a modified QEMU although work is underway to get the required changes upstream.

KVM VPS vs OpenVZ/Virtuozzo vs Xen

	KVM VPS	OpenVZ	Xen
Dedicated filesystem of your choice (with direct block level access)		-
Dedicated RAM with full access and debugging capabilities		-
Dedicated server like isolation		-
VNC connection from the very early boot stage		-	Limited Support
PPTP VPN		Limited Support
Open VPN		Limited Support
IPSec VPN		-	Limited Support
Firewall Configuration		Limited Support
Kernel mode NFS Server		-	-
Independent kernel		-	Limited Support
Independent kernel modules		-	Limited Support
Full control on sockets and processes		-	-
Full guest OS support (Windows, Linux, BSD, OpenSolaris, etc.)		-	Limited Support
Direct dedicated access to PCI / PCIe cards		-	Limited Support
Fine grained swap configuration per VPS		-	Limited Support
Official integration with the Linux kernel		-

Main features of KVM VPS are:

• KVM virtualization technology offers VNC support that gives you full, physical-like access to the console of your VPS.
• RAM and disk are not shared with other virtual machines on the main server. This makes your KVM VPS even more stable and excludes a possibility of overselling.
• KVM VPS allows you to choose custom kernels as well as custom kernel modules for your KVM VPS guest OS.
• You may set up a VPN server in KVM VPS (PPTP, OpenVPN, IPSec).
• Full guest OS support. Allows you to install Windows, Linux, BSD, OpenSolaris, etc.
• With KVM VPS you may run a Window manger such as Gnome or KDE and and interact with it using VNC.