I’ve been using Cloud66 for about a year to run a fairly complex rails app that has been in development for about 6 years. Strikes a nice balance of owning the infra while having it managed.
The docs could use a lot of work though, and I find upgrading things like Ruby versions far more annoying than it should be.
Previously used Dokku for a few years then it was on heroku before that. Switched off dokku to outsource more of the ops.