Its almost great, but the shortcomings / awful design decisions are deal breakers for me.

It’s required folder structure is not compatible with calibre’s required folder structure. Kavita will drop books on the floor while importing a series with multiple authors from your calibre library. They dont see this as an issue and claim there is other software to edit epub metadata (there isnt, really). Editing metadata on Kavita itself wont be reflected into your epubs when you send them to a device.

By default Kavita bounces all emails through the project owners gmail account & web server. This is… an insane decison and I have no clue how they think its a good idea. You can self host their email server yourself, but its yet another thing to setup and run.

Calibre-web is ok, but the owner is MIA for ages as far as i can tell. One person does seem to have commit access that is somewhat active, but good PRs have been open languishing for months and month at this point.