Gregory's Server
@Mastodon unlike many others responding here, I’m OK with the default onboarding of the official app going to the mastodon.social server. That’s an experience the Mastodon org can control and make work well. I haven’t seen any better suggestions and clearly the current setup is confusing.
Round robin could potentially be worse: randomly ended one place or another, and with subtly different rules. I found filtering by interest bad too: many have broad interests.
@Mastodon what would be nice if it was possible to create unique app download referrals (that an instance itself could use as links into e.g. the AppStore) that would then switch the default server to another one. That way instance admins could provide easy download links that would helpfully guide a user through signup to that particular server.