Mastedon because it is open-source & completely federated/distributed. No one owns your social graph but you and it has tools for finding your former Twitter/X friends on Mastedon. It's super active and most of my interactions with people have been positive and interesting.
Both; I've been on Mastodon since Twitter imploded a couple years back (well, I think I had an account since the last time Twitter toyed with banning third-party clients in 2018 or so, but I didn't use it at that point), and had a Bluesky account since early 2023, but didn't use it until a few months ago when it abruptly gained serious traction.
These days I mostly use Bluesky; it is more _fun_, which is the main thing I'm hoping to get out of twitter-esque services.
I've had a Mastodon account for years, but never used it. Newer twitter-clones also fail to interest me, simply because user-driven social media just isn't all that engaging for me. Topic-driven or article-driven like old-school forums or HN/Slashdot/etc. produce much better discussion and are less annoying to navigate and curate.
I find it easier to curate a community and keep out the assholes and bots.
Eventually that will change as these platforms become popular enough for the mainstream to show up and ruin, and I will have to move to greener pastures. But for now it's good.
I've only used social media to host giveaways and have a presence for some of my sites. Bluesky and Mastodon don't have a big enough overlap with my users.
Bluesky has moderation figured out and they hide rude comments by default so the habit of being rude doesn't spread as easily. The downside is it feels a lot more passive aggressive. Like instead of criticizing conservatives who vote for Trump, people would criticize conservatives who vote for Hitler.
