Conversations is brilliant, but I have yet to see a decent XMPP client for iOS. There's Chat Secure, but when my friends used that it often wouldn't receive notifications, making it useless as a messenger.
I'm not sure if this was a limitation of iOS itself (probably) or just a poor implementation (Chat Secure definitely tries to do something with push notifications.)
It's difficult to use XMPP when most of my friends+family use iOS
