This is the first step in the process leading towards a stable and supported XenForo 2.0.0 release. While we gather feedback and fix bugs with the demo, we'll be finishing off some behind the scenes work. Once we're happy with the state of the demo, the next step will be a developer preview release. This will be targeted at developers so they can start integrating with the XenForo 2 core code, but anyone with the necessary technical ability (and active license) will be able to install and play with it. After that, we'd follow the same beta process as previous 1.x releases.
If you have any feedback or you've noticed a bug, please let us know on the demo forum itself.