>>34179 (OP)virt-manager is convinent GUI wrapper for qemu which uses kvms.
It performs significantly better than virtualbox. You can setup/migrate same VMs in both and test it yourself, easy to verify.
If you want to do passthrough stuff also virt-manager/kvm is the only way (Which is also the only way to get decent graphics performance inside a guest with nvidia since nvidia is jewish and they don't let you accelerate guests in Linux)