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.
frightful_hobgoblin gave a pretty good rough overview of the bigger instances.
Some instances are more geared towards a certain "culture". Once you browse enough of Lemmy you tend to get a feel for it. For instance, I chose my instance because a lot of the communities are centered around hobbies and interests so it's more lighthearted, and the admins seem to be very focused on providing a positive experience as well as ensuring federation is done right. You'll just need to keep this culture of an instance in mind when browsing communities on different instances. The level of moderation can vary significantly between them.
I haven't tried it myself but my understanding is you can move your account to a different instance should you choose to in the future. So keep that in mind if you feel like at one point you don't like your instance.