I’d pretty routinely have federation issues, missing posts from my TL, and posts that would just repeat endlessly in the TL until I reloaded the page. And those are problems I experienced on every fork I tried.

From what I've heard, they've all inherited these very same issues from Misskey. And apparently, they aren't trivial to fix, otherwise either Misskey or any of the Forkeys would have succeeded.

I guess your best bet is to wait for Iceshrimp.NET going fully public and ideally stable. It's no longer a Forkey. It's rather a complete re-write from scratch of Iceshrimp, no longer in TypeScript and Vue.js, but in C#. Apparently, Misskey's codebase (plus what Calckey/Firefish added) was so bad that this was the most promising step to take.

Also, app support isn’t great.

Found the former Sharkey user.

Sharkey's Mastodon API implementation is infamously terrible. The Sharkey community is still waiting for someone to step in and re-write the Mastodon API implementation from the ground up, so bad is it.

But another issue is that everyone who could theoretically develop a mobile Fediverse app is on Mastodon. And so, instead of a good *key app, you get yet another Mastodon-only iPhone app and yet another Mastodon-only iPhone app from people who don't even know that the Fediverse is more than Mastodon.