The beta is the most stable currently available.
New features roll out pretty much like this - the further they are down the line, the more stable they will be:
- Canary → Experimental → Beta → Stable (a stable release has not yet been released as of 2018-06-14)
Here’s a more detailed description of teach channel:
If you’re curious about what the primary changes are between releases, you can look at the Releases category.