CouchDB just isn't very nice to use. Compared to MongoDB or RethinkDB, it really isn't any fun. You can't do ad-hoc queries and it doesn't give you the tools to properly write/test your map/reduce/rereduce functions. I still don't know how trying the rereduce step is supposed to work.

To make matters worse, the used JS engine is fairly old and the exceedingly wordy documentation is kinda hard to follow.

I'm a lot happier with RethinkDB.