Installing a "Beta" of Ubuntu is a misconception.
There are only installation media labeled "Beta", but what you are going to install is the development version and it will identify itself as
Ubuntu Happy Codename (development branch). Once development phase is completed, it will receive an update of the
base-files package which will make it identify itself from there on as
Ubuntu 00.00 and will behave like any other installation. This also includes receiving release upgrades depending on the update policy.
You can also upgrade an existing installation to a development release at any time. However, you should be aware of what questions are appropriate for "ubuntu+1".
And of course be careful when updating the development branch, as
Jo-Erlend Schinstad already said in his answer. Generally it's not particularly dangerous to run the development version on secondary devices during the last weeks of the development process, but when something does go wrong despite all QA effort, it happens when you really have better things you would want to do.