I too couldn't decide, so I started my own private instance recently (it was dead simple with the docker stack), and sometimes I feel a bit isolated and wonder if I should have joined an established instance instead. I suppose that's the burden one takes upon with a private instance: you have to actively go out and find people to follow and interact with. The advantage of course being that you're not bound by any sort of community rules or norms, and all the other advantages of hosting your own services. In any case my main goal was to get myself to write more, regardless of who's reading it, so to that end it's been successful.