Are there chat systems providing a human-like conversational experience?
This is a can of worms. Because, beauty is in the eye of the beholder. And therein lies the crux of the problem of computing natural language. Until now, there has only been the infamous Turing test, to determine what is human-like and what is not. And the only bold implementation of that has been the much maligned Loebner Prize. So, according to the Loebner Prize, Bruce Wilcox’ Rose is the most human-like dialog system today. What I can say about Rose is that it is highly, extensively hand-tooled, and not of the fully automated variety at all.