With KVM, your VPS works almost like a dedicated server. OpenVZ is container-based virtualization for Linux, and not all kernel modules are available. The main disadvantage of OpenVZ is that you can only use an OS template, and there is no option to install an OS manually. KVM supports Linux, BSD, and Windows; and has flexible migration capabilities. KVM will get you a separate virtual disk, graphics adapter, and network card for each instance.