I thought I should chime in here since I’ve tried both recently. I run a gaming forum and I have a large Discord server (~50-100k). I originally came from IPS (Invision Power Suite). That was about 8 years ago when XenForo, myBB, and IPS were kind of the leading forum softwares out there. Now, in 2020, I wanted to update myself. I took a quick glance and saw the best modern options were nodeBB, flarum, and Discourse, but I dropped nodeBB since it didn’t have the infinite scroll and still used page numbers to flip through threads.
I started with Flarum. Very easy install. I totally configured most of what I wanted. The admin panel was very simple. The user permission system was something I like (and still believe it to be superior to Discourse). However, it was too basic that it lacked many features. There was no user management system. Rather, I had to install an extension for user directory which would appear in the sidebar of the homepage. I couldn’t search for users easily to assign them user groups. I had to visit each of their user profiles individually.
The theming in flarum doesn’t have as much documentation as I would’ve liked. I asked around to get answers on how to change the custom CSS to change simple things like my header font color. I noticed on the flarum forums, it was a question that was asked a lot, but then it should be documented so that people can do theming more easily.
Flarum is faster and snappier. It’s more lightweight, but it lacks many extensions. It has a smaller dev team and they are working very hard. However, I guess since Discourse has been around longer, there are more plugins, more theme components, etc. People have tested this and given a lot of feedback to make and fix most of the issues. Flarum is still in beta and it is recommended to not be used in production as well.
There was a simple extension I was looking for - the topic list thumbnails. I couldn’t find it on Flarum. It was told to me that would be easy to create this on Flarum using CSS, but when asked how - no answer. This is their docs for appearance atm, it’s empty: https://docs.flarum.org/appearance.html Given that I can’t spend the time and effort in trying to develop my own extensions that already exist in Discourse nor can I commission developers to prioritize my needs, I went with Discourse finally.
I’d also say one big advantage to Flarum is that it can be used on shared hosting. I use a VPS so it doesn’t matter, but because Flarum has PHP, it can be used on shared which is why some users will go for it. Flarum is simple to install relatively compared to Discourse.
It did take an awfully long time to configure Discourse, more than I imagined. There were was much more complexity because I had already flarum on my server so I had to configure the yml to run on a different port. I certainly don’t like the “wizard”. I prefer to just have a standard docker-composer.yml and then configure it. This is the reason I started with bitnami but I soon learned that they have outdated images, so I am now on the current install.
I can say, with confidence that there is lots of good documentation for most of the things I want to do and lots of help in Discourse. Don’t get me wrong, even Discourse doesn’t have everything, but it is closer to the perfect forum that I need. I do believe Flarum will offer the same functionality eventually in terms of plugins / extensions but I can’t wait that long.