Benchmark: peaks at around 17,699 jobs/sec for one queue on one node. Probably covers most apps.
https://getoban.pro/articles/one-million-jobs-a-minute-with-...
We've also had a lot of experience with with other libraries like Que ( https://github.com/que-rb/que ) and Sidekiq (https://sidekiq.org/) which have certainly influenced us over the years.
You said back then that you planned on pursuing a Go client; now, four years later, here we are. River looks excellent, and the blog post does a fantastic job explaining all the benefits of job queues in Postgres.