OpenVZ and templates

Hi,

Playing with Proxmox and i've got some questions:

How safe is it to use pre made templates from sites like: http://download.openvz.org/template/precreated/

Do you trust them or do you create your own the tar.gz and move it across?

Also when would you use OpenVZ and when would you prefer KVM? I know OpenVZ shares kernel so it saves on RAM / CPU but you're in turn limited to your hosts kernel version.

So when do you opt for KVM and when for OpenVZ? Any reasons/preferences?

Thanks,