Discourse is pretty great:
– works as forum as well as a mailing list
– the mobile version is highly usable, reading threads is a comfortable experience.
– search is powerful and efficient
– designed to facilitate community management and moderation
– on the server side, it's easy to update
On everything else: Android devices (Chrome and Firefox), Windows Phone, Firefox OS, you name it: the initial page loading time is slow enough so that each time, compared to another website you start to wonder if the website froze, your Internet connection dropped or who knows what.
And there's no loading progress indicating that something is happening.
Sometimes you don't bet on the right software stack for your need and it's a painful realization.
This thread is a example of that, and you see plenty of denial, blame shifting and other defense mechanisms going on.
They might still get away with it with a work-around making the initial page load and display much faster thanks to server-side rendering tho. And loading all the heavy stuff once the content is already visible.