I spent a few days with Betaout, working my way through its features. It's not really a good fit for my current team, because we're just too small to benefit from many of the features, but for a larger, more traditionally-structured editorial team, I can definitely see how it would streamline the workflow and keep the team organized. If the day ever comes when I can primarily be an editor and have others fill the additional roles, I will come back to it.
Its disadvantage for smaller teams is that it is constrained by the "one role per user" limitation of WordPress. So, if you are both the editor and one of the writers for your site, you have to pretend to be two or more people. However, even though it pulls the user accounts from WP, it does not tie itself to the log-in state. You can be signed into the Newsroom as the editor, and the Workbench with the writer account at the same time.
The only other issue I ran into is that it is unable to ignore certain custom post types that may be added by other plugins. For example, I use an admin to-do list plugin that utilizes a custom post type to store the entries in the database. Betaout sees these as published posts, even though they actually only show up in WP admin.
I emailed Betaout inquiring about the latter issue, and ended up having a wonderful email exchange. The people there seem very interested in what users actually need and why their product doesn't fit that need. Even if I don't end up needing Betaout in the future, that is enough to make me keep an eye on their future offerings.