Interesting article on ZDNet about a recent competition administered by Facebook's AI researchers, with help from Microsoft and others, to show the state of the art in chatbots. The overall result was "soul-crushingly boring and nonsensical" according to ZDNet.
But an interesting perspective was then posted by one of the stalwarts on chatbots.org, who, recognising that most of the bots tested were "modern" ones developed by commercial start-ups and based around machine learning/neural net algorithms said "This reinforces my belief that using a neural network for a chatbot instead of being rule based is simply not an option. I have yet to see any neural net based bot that was any good.".
Think I'd tend to agree.