So, I trust myself so much that I switched to my PostgreSQL version of BlogEngine.NET. It seems to run quite fine, at least as well as the original one. There are some issues I don't like and I will probably address them.
The engine includes a lot of caching. So much so that when I create a new blog post and click Publish the caches are not refreshed and the post is not visible. I will have to poke around a bit and make it refresh. I don't want to reload the whole application after each post.
I've disabled all caching on the web server so it's not that. It's something inside the system. And seems quite many people have issues with it.
Also since the system is DB backed now, there might not be that much need for aggressive caching. At the moment the system loads all posts, comments etc into memory and keeps them there. It's not rational when there might be a lot of them and some are not accessed in a very long time.
I'll have to poke around and remove the cache and let LINQ handle things from there.
Also looks like there's some nasty bug in the date handling. If only everything was stored in UTC. I'll have to change that also.