Well I've been on Mastadon a week or so now.
Mastadon is not twitter. It's more conversational and is more interaction oriented. So far there doesn't seem to be a lot of reposting of links, more original material and content, but perhaps that will change, but at the moment it's more like a bulletin board, or even usenet news.
I've found it a useful, even stimulating experience.
But because the platforms are so culturally different I'm still in a quandary as to what to do about twitter.
For the moment, I'm using twitter as I always have, but posting more original material to Mastadon as @firstname.lastname@example.org.
I probably don't have the bandwidth to do both for a long period of time, but I'll wait until Mastadon settles down before deciding to jump ship ...