Is there any difference between Lemmy instances? If so, what are they? How do people choose an instance? How does one decide one instance over another?

On a related topic, do you have any opinions about specific instances? Not trying to start a beef battle or anything. Just curious in learning more.

I personally found a “service” about Lemmy instances about a year ago, with half a dozen instances “highlighted”, advising picking a popular but not too popular one, so I chose the one I use now (though I use Jerboa, extremely rarely the website). Now, I’m curious about learning more and seeing what other options could offer, if anything (not that I ever had any problem with Lemmy Today). Having an alternative could also be useful if there is ever an outage in one instance.