Dokku is available now. This landing page says RepoBus will have "Deploy to multiple servers", "Aggregated logs + search", and "Aggregated metrics + alerts" (and maybe others) that I think Dokku doesn't have.

Dokku does have deployment to multiple servers, albeit plugins to deploy to a kubernetes[1] or nomad[2] cluster.

[1] https://github.com/dokku/dokku-scheduler-kubernetes [2] https://github.com/dokku/dokku-scheduler-nomad

Perhaps to answer the question, one might ask: How is Heroku different from Dokku?

Having used both extensively, the answer is as simple as one is private/hosted and the other is open/self-hosting.

Heroku is easy, but expensive. Dokku is more work/management, but cost-effective.

For one, Heroku has dedicated customer support when you pay them.

Right, dedicated support should be available at launch. Thanks for the feedback.

That difference is very clear: you still need to buy and manage your own (cloud) server to run dokku on.