The only problem I have with Mastodon is that it's hard to discover new things.
If you already have some people you know who to follow that's great, but there is hardly any discovery or recommendation beyond that.
Also isn't that the point of a micro-blogging platform that the discoveries are made through the “retweet” of the users you follow? For years that used to be the main way discovery worked on Twitter, before they moved to algorithmically curated feed (which became full of “high-engagement” crap pretty soon).