Mastodon is very Twitter like. It's focus is on implementing the main features and it's just the software most users use. Then there's also other software like Misskey (and Calckey (which I run on my server) as well as some other fork of which I've forgotten the name). Misskey (and its forks) implement additional features that Mastodon doesn't have and don't use the Mastodon API. So using Mastodon apps with them won't work as good. There are Misskey apps though.
My personal opinion is, that Misskey and Calckey have a better and more modern approach in regards to UI/UX-Design. However that's subjective. Misskey and Calckey also have additional features like longer posts (3000 characters per default with Calckey), pages, clips, drive and much more. Misskey and Calckey also use Reactions instead of "Favorites" which means that if you react with a 🎉 emoji to a post users on Misskey and Calckey will see that emoji as a reaction. Mastodon users will just see it as a favorite (so as a star).
In general I used Mastodon for quite a while and switched to running my own Calckey server at calckey.braydmedia.de