Dino.im crashes too frequently for my tastes. It also doesn't have an official Windows version. Gajim looks outdated and the update procedure broke several times (I know the authors are working hard to modernize it though).

iOS story is sad. Family used Snikket (thanks for your work on it) but it still dropped notifications even after following with issues and Prosody modules needed. (Monal seems to be okayish now).

Even Conversations.im seems stuck. I know everyone has their favorite missing feature but for me no reactions is the biggest.