Not OP, so I don't have to bear the snark, but also, let's not pretend that iMessage is some virtuous and ethical standard worth recommending in general. It's nothing but a tool by the monopolist Apple to execute vendor lock-in and subjugate its users into a closed ecosystem. Of course, that says nothing about the quality of said ecosystem (or that of XMPP, for that matter), only about a well-placed sense of priorities that I find laudable.