I’ve tinkered with a few SBC’s in the past, including the Raspberry Pi 1 and 3 (and the NanoPi Neo).
IMHO, The Raspberry Pi 4 is the first SBC that I would actually take seriously, for running any sort of server like Discourse on. Thereby putting it in a class of it’s own.
The Operating Systems that are provided with other non-Raspberry Pi SBC’s (for example, Armbian) tend to have flaky seen-in-ARM-but-not-in-AMD64 bugs lying in wait, which to me sort of disqualifies those boards for serious consideration, as these not infrequent gotchas will be very taxing. Having said this, I give huge kudos to the Armbian project, who are truly doing the best they can to bring stability to a highly eclectic bunch of ARM boards which are surprisingly different from one vendor to another.
It’s only the Raspberry Pi ecosystem where you see major development work to make the OS as stable and reliable as I would like, for running a server like DIscourse on. As to the Raspberry Pi 3 and down, they don’t have USB 3.0 (ouch, disk IO nowhere as fast as I would like for a server, like 20 MB/sec at best), nor true gigabit ethernet, again disqualifying them from my consideration as worthy for a server for software like Discord.
So that was my reasoning behind why the Raspberry Pi 4 deserved it’s own thread. It’s not a trivial thing, I say, that the Raspberry Pi 4 has arrived, which is a very decent and cheap SBC for making a server out of, where so many other SBC’s came nowhere close to cutting the mustard, in the way of hardware, and software stability.