Here are some advantage of Container virtualization
Container virtualization, meanwhile, also known as “operating system-level virtualization”, allows multiple instances to be run on the same computer, but with each one isolated from the next and sharing only a minimum of resources.

According to recent paper published at Princeton University, there are scenarios in which a container-based solution will prove to be more effective than a hypervisor-based one, especially in “scenarios that require system virtualization with high degrees of both isolation and efficiency”.
a well-managed container-based virtualization system can outperform that of a hypervisor, but at the cost of an openness to resources.
http://myhosting.com/blog/2011/06/vi...irtualization/