I joined the Beehaw instance a bit ago with a small exodus from Tildes, another Reddit alternative. It's been nice to see the community grow and grow steadily as time progressed, and seeing the Reddit refugees makes me hopeful for the platform's strength going into the future regardless of what Reddit does with its API (or other features).
As for the toxic side of Reddit, I'm more concerned for the devs in having to deal with the reports, but as a Reddit mod myself, I don't think it'll be too bad. At least on Beehaw we have a supportive community and I'm reminded of a video talking about the userbase of the early UseNet and how they dealt with the first spammer (not necessarily their methods, but the fact that they rose up as a community to enforce a community rule). Hopefully we can see that here (i.e. "the report button exists").
I'm a long time (mostly lurker) user on Tildes and I'm wondering this too. I just did a quick search over there and I don't see any mention of it, so it doesn't seem like the exodus was publicly advertised at first glance.