I'm pretty active in r/3DPrinting and r/FixMyPrint, and strongly support the blackout. I've been avoiding Reddit entirely and getting my news from other sources, while also exploring the fediverse. I had no idea about the rhombik instance/magazine/whatever.
The core problem with the migration is that the information on where to go EXACTLY is hosted on the platform being boycotted. I decided to not visit Reddit anymore and watch for instances to pop up on the fediverse. If others do the same, the migration will be slow. Don't be discouraged if it takes a few days to pick up steam. There's another 3DPrinting magazine that has some users already. https://kbin.social/m/3dprinting@lemmy.world or https://lemmy.world/c/3dprinting
That leads to the second problem of on-boarding migrating users to a highly distributed platform. I've mentioned in the boycott server the need for "racks" (the subjects within instances are called magazines, this would be a collection). These would be moderated aggregators of instances, like the invisible step between lots of disparate subreddits. There would be no limit of the number of racks, so technically you could have a permutation of every associated magazine-instance combination. The purpose would be to have a single link new users can click on to get subscribed to a set of magazines all at once, basically making the federation concept seamless to less technical users while still highly flexible on the backend. I'm going to shoot the suggestion up the chain for kbin.
We want to avoid leaving folks like this: https://lemmy.world/post/97417
That leads to the third problem, which is all these alternatives are new and going through growing pains. Trying to add features comes second to keeping the service stable. I'm hoping others with more coding experience can assist kbin devs.
And I wanted to mention that last I heard (and saw evidence of), some of the main Lemmy devs were kinda garbage people (Tiananmen Square massacre supporters, not just questionable opinions on government). The more controversial instances have been defederated from the primary/intake server, but it's still worth mentioning. Kbin doesn't have that baggage, but there are only a couple devs, and really only one main dev, last I heard.
Kbin users can see and respond to Lemmy and Mastodon instances that are federated, so it has been the migration choice for most of the Reddit boycott groups.
edit: btw - I just looked at the comments on the one post. If you want to run a poll, fine, but most of the people protesting won't be there to vote. I thought the 3D printing subs were largely positive and supporting, if those comments represent the community I was supporting, I now have zero qualms about deleting my comments on Reddit.