Just came across this discussion and wanted to bump it up. My friend got a test site running in under 30 minutes (installed via YunoHost), even though she's not the "tech savvy" kind, so I'd say a lot of the "initial" install bumps have gone since this thread was last created.
I came across Flarum because I was initially thinking Discourse (the default option these days, it seemed), but then I found I need a VPS, and Docker, and 2GB RAM and whatnot. Most other forum software, if well designed on the backend, are pretty ugly to look at (or shall we say, out of their time). Flarum's the only one I found that's got reasonable features and is also aesthetically pleasing.
I haven't explored much yet, but from first impressions this seems pretty awesome, and I've had nothing to complain about so far. if people think removing "don't use this in production" warning isn't a good idea, perhaps it could at least be toned down a bit?