Not an mbin dev, but I do hang out in the matrix channel (because their app support is amazing).
I've brought up mbin a few times in various threads. I don't like to advertise as such, but if someone wants to know what my setup is, or is otherwise interested in self-hosting, I absolutely offer it as a suggestion.
After kbin.social died, and I didn't want to restart somewhere else just to have it die too, so I opted to self-host.
Why mbin rather than PieFed? For me, I started using it because it does threads and microbloging, and I didn't want to run two servers (and Mastodon install is a pain in the ass). I continue to endorse it because they keep fixing the problems I have with it, and they aren't jerks about bug reports. And they actually respond in chat (unlike the dead SearXNG chat).
I haven't seen any spamming (other than my own), so if you're gonna shit on them, maybe come up with some examples. As for their temperament, they've always been helpful, responsive, and pleasant to communicate with (as least with me).