Amaroq is another pretty good iOS client: https://itunes.apple.com/us/app/amarok-for-mastodon/id1214116200?ls=1&mt=8
linking to federated users is a PITA though... and it doesn’t seem to update your timeline when you post, so you don’t know if it succeeded. mastodon.social is dragging too, which affects app performance. it could use some more caching/background activity