Also remember not to let the existence of something even done well stop you from creating. There's lots of room for differentiating--it's not one size fits all. Pretailored is what the market needs.
I often myself end up doing side projects and weeks later, regret not having done more research on existing solutions as I find one that covers my needs far better than I could have covered them myself.
I'm just gapd to have found a side project I might keep up with.
I think my differentiator is 'lighter' but with a little more than Trello had.
I haven't compared them recently, but maintaining a project, "on-top" of GitHub front-end, seem quite a difficult task.
I wish we could reuse GitHub projects instead of having the projects be stored on the zenhub API. But GH projects are super lackluster still especially in terms of permissions.
Best UX / design I've seen for boards.
I also use the Slack email app/integration to give each user in my org an address, and then pipe GitHub notifications to their own `#gh-username` channel. This brings GitHub comments out of email, with minimal disruption.
I'm hoping ZenHub adds a tasks feature that would let us assign/receive/track issue-based tasks. That's an important workflow tool we're currently lacking, but we're reluctant to add another tool to our chain.
I'm a big fan of ZH; the cross-project kanban board alone gives a huge productivity boost if you have multiple related projects with their own issue tracker.