It handles tens of billions of messages per day for Whatsapp, that is successful.
Riak and RabbitMQ handle a lot of data and messages for many companies.
Ejabberd and derivatives are probably the default enterprise chat/XMPP backends.
If anything one can argue it is more successful than any of those technologies.
What are node's success stories? Paypal, Walmart, New York times. I haven't been following but those are ones I remember using it.