Most usable driver for full virtualization

[Vitaly Potyarkin]

Hello,

What's currently the most usable driver to provide full virtualization? Vagrant was described as alpha quality even before it was evicted from main tree. Seems to be broken as a plugin (at the moment).

Is libvirt worth looking forward to? The docs advise against installing it yet.

Should I better look into delegated? 

Thanks.

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Vitaly