I use a KVM for exactly that and it's fine. But I don't do any 3D stuff: if you do 3D stuff and you need passthrough acceleration VBox is really the only option you have ATM. (FWIW, the Fedora kernel and virt devs are unified in viewing VBox as a terrible, terrible piece of software; they obviously think KVM is the best thing ever, but it's not just competition-syndrome, they think VMware and Xen are perfectly fine code, it's just VBox they think is really terrible).
What about snapshots with KVM? And do you use gnome boxes?