[blitzclone]

The name KVM is a bit confusing. It doesn't do anything fundamental different than VirtualBox. The difference is that KVM comes by default with any Linux. VirtualBox ships it's own Linux kernel module for that. That has drawbacks. You typically can't use the newest Linux or the newest features.

KVM also always has the hottest new (performance-relevant) features, because Intel and AMD will always build their hot stuff into KVM first.