I really feel like it doesn't matter what you use as long as it's part of the Fediverse. If whatever you've chosen is federated we all benefit. I feel that ever since Kbin federated there's way more content even on Lemmy. I'm just glad that we can all see and interact with one another.
That’s true. Though the fear of defederation (and in turn isolation) is always there. I wish they make it so that the users, not the admin chooses which instance to defederate. But maybe this is too tedious to implement.
If your instance defederates from an instance, or you are defederated from an instance you enjoy, you can always move to a new account. Unlike Reddit, you don't have Karma to link you to your account so you can just move over to a different instance (although subscribing to all of your favorite communities again is a pain in the ass)
I guess that is a solution. But I agree creating a new account means starting over, looking for communities once again and maybe your post history, plus the hassle of having to manage two separate accounts. I guess the issue of fragmentation in the fediverse needs to be addressed too as it matures.