Very interesting read, and more so the comments here with all the various experiences. I'm the author of Event Horizon for Go [1] which is currently being developed along side a project that uses it, in this case a CRM-like system where the audit log is a selling point. We still have a lot of unsolved areas but as some have noted it is a very rewarding developer experience. How it behaves in production is still to be seen, but reading here has given me a few good insights to prepare.

[1] https://github.com/looplab/eventhorizon