There’s also some feature differences between instances. Some instances disable downvotes, don’t allow creating communities, or have stricter rules about communities that are allowed.

I chose my current instance because I wanted downvotes (I see them as critical for quality control) and also wanted to be federated with beehaw.

As an aside, LW made massive performance improvements the other day. They seem to be in a good position to keep growing, currently. There’s certainly some benefits to being on the biggest instance, because of how the /all feed works. It’s not actually all. It’s “all communities someone on my instance subscribes to”, so the bigger your instance, the more correct /all is.