I've mixed feelings about it. As advertised it can be somewhat useful for business rules-rich apps, yes, but most of the times the application side of the project will just grow exponentially faster than your core - especially if you don't keep an eye on commits, as some of your coworkers may choose the easy way out and push business logic on the application side instead of refactoring... It's a clean architecture from a business logic standpoint, indeed, but it doesn't do a lot to keep the outside of the hexagone well organized (beside the port/adapter pattern), and that side of the app can grow into a mess really fast if your team lack experience.

Not as many abstraction layers than in a classic J2EE app, though. It's not that bad.

I use it all the time. It is my default architecture choice. It works great in my opinion. I wonder why you think there is a lot of ceremony needed? The core idea doesn’t require much. The Hexagonal Architecture idea can be implemented in many ways. I recommend Googling “Elm Architecture” to see an example. It isn’t described as being a Hexagonal Architecture but I will argue that it is one of the best ways to implement it I have seen. It has zero ceremony (a few functions define the whole architecture).