[ncza]

If I recall correctly the issue with ios xmpp clients is that you cannot run them in the background. Instead you must either have a provider that does push notifications or the client has to run constantly, draining the battery and closing automatically every now and then. At least that was the fatal result when I tried to convince friends to use xmpp a while ago.

[bdkoepke]

I personally don't use iOS so I'm not sure whether that is still an issue. They released an update for the iOS client fairly recently so you could give that a shot? The new iOS client seems like it is very nice: https://chatsecure.org.

[hackerboos]

If I recall correctly the issue with ios xmpp clients is that you cannot run them in the background.

Why isn't this a problem for Android or Windows phone?

[easytiger]

iOS has limited support for background processes.