The learning curve is steep, it has a bunch of rough edges (it's still not reached a v1 as of the time of writing), you end up living in YAML and by any reasonable measure, it's only usable by geeks who are happy living in a world unfamiliar to most mere mortals.

FWIW this isn't true anymore. Most stuff is configured through the UI now (there's even a bunch of integrations that don't even support YAML configuration, just UI configuration). There's still a learning curve to be sure, and there's still functionality that does require editing YAML to handle, but my impression with setting it up now is that it's actually pretty easy to get off and running with just the UI.