(Does this still count as a viable NANY item for 2019? )
So, no, I don't really use it. But I had some friendly encounters with the devs, I was one of the first German translators, and I like how well they respond to feature requests. ElkArte was the first forum software which crossed my ways and had built-in OpenID support.
It rose from the ashes of SMF when they made it Free Software and it is the only one of the six or seven subsequent forks that still sees public releases every few months. SMF has moved on, sure, but ElkArte has some former SMF devs and much less bureaucracy. Yet. Original address: https://www.donationcoder.com/forum/index.php?topic=45474.0