Vagrant 1.1 is the first release in Vagrant's history that is provider-agnostic. I'm shipping a Fusion provider and open source AWS and RackSpace provider, but the interface itself is completely open source and documented, meaning anyone can add their own providers: http://docs.vagrantup.com/v2/plugins/providers.html
And the provider API was introduced while retaining full compatibility for stock Vagrant 1.0.x installs. I'm really proud of that achievement. Vagrant 1.1 is a drop-in replacement for many organizations.
Vagrant 1.1 is already in use in production at many large organizations, the biggest of which at the moment may be Yammer. The QA process for 1.1 was actually done by shipping to the big companies first. That was quite an experience, but I think that will result in a stable 1.1 experience for the masses.
Anyways, I'm here to answer any questions if you have them.