We have this BETA running in a few select production environment and there are many small known issues.
With this and the next couple releases, we are focusing on the Upgrade Process and Conversion to the new file formats. That is why there is an explanation in this thread on how to read the Conversion Page.
More information will be explained in a Blog Post.
Anyone and Everyone who tests these BETA's will be guaranteed flawless upgrades because the Developers are available to discuss any and issues that occur in your testing.
Later in the BETA we will give the OK on going to production and that we will support you through the community in a timely manner... but conversion issues will be difficult to repair on a production server and why we want to make sure we catch most of the conversion issues on test environments.