VirtualBox is ridiculously simple to set up and get virtual machines going. Shared folders, shared clipboard and much more are no issue.
But.
It eats resources. The installed virtual machines (VM) run relatively slow. What have you found to be feature comparable - and most importantly more resource-efficient - alternatives for running VMs under Linux?
I use Quickemu for mine, makes it really quick and easy to get a new system up and running.