For a customer of mine I was researching whether we could use LXC for virtualisation. The customer is migrating to Debian 7, which does not contain OpenVZ anymore.

Although the Debian template bug is still not fixed, I first thought it would still be usable when writing our own templates. But it turns out that LXC still allows to execute code as root on the host since 2011.

More background information for those of you who are currently considering LXC:

So for the moment my recommendation is QEMU (KVM has been merged back into QEMU!).