Within my XMPP-based community, I've had most users profess a strong preference for the 'monocles chat' client over Conversations for having better stability and a little more featureful, with everyone having tried Conversations first:
https://f-droid.org/en/packages/de.monocles.chat/
Either way, regardless of user preference, it all still interoperates per the nature of a proper federated instant messaging protocol.

It would be nice if someone filled the gap for a reasonable-quality iOS client some day, of something that fits within the iOS HIG design standards.