One of the first pain points I've been attempting to help smooth out was how Juju is packaged and consumed. The Juju QA Team have put together a new daily ppa you can use, dubbed the Juju Daily ppa. It contains the latest blessed builds from CI testing. Installing this ppa and upgrading regularly allows you to stay in sync with the absolute latest version of Juju that passes our CI testing.
Naturally, this ppa is intended for those who like living on the edge, so it's not recommended for production use. If you find bugs, we'd love to hear about them!
To add the ppa, you will need to add ppa:juju/daily to your software sources.
sudo add-apt-repository ppa:juju/daily
Do be aware that adding this ppa will upgrade any version of Juju you may have installed. Also note this ppa contains builds without published streams, so you will need to generate or acquire streams on your own. For most users, this means you should pass --upload-tools during the bootstrap process. However you may also pass the agent-metadata-url and agent-stream as config options. See the ppa description and simplestreams documentation for more details.
Finally, should you wish to revert to a stable version of Juju, you can use the ppa-purge tool to remove the daily ppa and the installed version of Juju.
I'd love to hear your feedback, and encourage you to give it a try.