Is it really a complete alternative? It looks like you have to host it yourself (one of the main appeals of Disqus was that you could add comments to any static page).
Also, it would be nice if they supported a SQLite backend, which would probably make more sense for small blogs running on very weak shared servers.
I've looked into using things by The Coral Project before but their documentation is just not there, there don't seem to be that many sites actually using their software yet, and their architecture is plain too complicated: it's split up into a bunch of microservices that aren't well documented.
I launched a service a while back that provides the infrastructure to do exactly this. Check my profile for a link of interested: hosted sqlite available over CORS. We're looking for early adopters.
Also, it would be nice if they supported a SQLite backend, which would probably make more sense for small blogs running on very weak shared servers.