Guys, you get what you pay for. Getting an OpenVZ VPS for 5$ is in no case better than paying 15$ for the same specs on Xen.
On Xen you have dedicated ressources (at least on HVM) and in openvz you share ressources. Same with KVM, since it is easily possible to use the same technique on KVM. On Xen there is no built in option for "overselling" or "ballooning"