I think there should be a review page for instances that allows comments. That would help immensely. The person reviewing has to have been, or is currently a subscriber and it's listed how long. The longer, the higher the review.

The better message instead of "it doesn't matter what instance you pick" should be "your choice of instance is not permanent." With any product choice, the rule of thumb is that most consumers will switch products only when they perceive a 10x improvement. It is clear from many similar threads that the sign-up process is a barrier to such perception, because of the cognitive load of having to choose. To me, there's two ways to address this: offering fewer choices, or reducing the perceived cost of a choice. In particular, streamlining account out settings migration (eg via export/import tools) may make arbitrary server choices more appealing, as it then becomes easier to pack up and switch.

So it does matter which server I choose? Will my choice mean I can’t see all the posts from every server?