Personally I love diaspora as it's designed around discoverability - following tags, people define themselves with tags etc.
While Fediverse, activity pub etc. are great they are full of holes when it comes to discovery an actual social content. Comments are difficult and non native and navigating tags is nigh on impossible.
With Mastodon, you can quickly create account you can send notes, links or images into. This account lives on the open web without registration required. You get Atom feed you can use to re-display the content in any way you want at other sites, or to share the content with people who don't use ActivityPub yet. You get "comments" for free for users willing to get ActivityPub account.
Federation largely avoids this problem. If the owner of my Mastodon instance starts doing stuff I don't like, I can switch to a different one or start my own and still interact with all the same people. (Hell, if the developers start doing stuff I don't like, I can even fork it or switch to an alternative program like Pleroma that uses the same protocol.)