The people I've seen who have talked about their engagement numbers--as measured by something like "how many visitors do we get to a story based on a Bluesky/Facebook/ex-Twitter/etc. link", so independent of the social media's self-reported metrics--have all reported that Twitter is generally among the poorest-performing social media sites. Especially if you're looking at it from a perspective of "how much engagement do we get on social media [likes, quotes, replies, etc.] per conversion to visiting the site," where it strongly looks like Twitter is massively inflating its reported engagement.
I don't know how true that was of Twitter pre-Musk takeover, especially as many of the most direct comparisons didn't exist back then, so I can't say if Musk's takeover specifically made it less effective or not.
Anecdotal, but everone that I've heard do those comparisons have done Bluesky vs X, and every time they've noticed better engagement ratio and higher quality engagement on Bluesky.
And I’ve seen people report the complete opposite. Both can be true. The reality is BlueSky pushed echo chambering even harder than X and it’s a dying platform - maybe those two things are unrelated but not for me they aren’t. Unless some miracle happens to reverse its trend, BlueSky already had its shot.
I have no interest in any of them. The Twitter-style format is inherently toxic and always devolves into a trolling competition or echo chambers. The short format prioritizes stupid takes that fit in a sentence or two over well thought out ideas.
I don't know how true that was of Twitter pre-Musk takeover, especially as many of the most direct comparisons didn't exist back then, so I can't say if Musk's takeover specifically made it less effective or not.