What is the crowd's opinion of phpVirtualbox?
From 3.5 billion comments

➔ phpVirtualbox website

By popularity online, this Service is:

#44 in Virtualization apps

2 reviews of this app found across the web:

The CLI tool virtualboxmanage ships with VirtualBox.

You might also consider phpVirtualBox for a web-based front end.

I'd say go with Proxmox. Or if you're really comfortable with Virtualbox there's a webgui for it and it's pretty trivial to get up and running.