ZenHub is a great plugin for GitHub. It adds a kanban style board to your GitHub issues. Zube is not a Chrome extension, it's a full web app. The reason we made it a web app is because we really wanted to focus on making a product that developers love. With Zube you don't have to go to GitHub issues, and we believe the experience on Zube is much better than GitHub Issues.

Also Zube is fast :)

You can see our focus on developers by the layout of our board, which is more scrum style than kanban. Each developer has their own row. It makes it easy to see exactly what your tasks are. You can also assign issues by dragging the card over to the user's row, something that isn't possible with a kanban board like ZenHub. We care less about getting an overview of the whole project (what PMs care about) and more about what needs to be done (what devs care about)

We'll continue adding features that make developers happy whether they would fit into the GitHub Issues paradigm or not.