I like that we can have live chat with our customers at any time during their day or night! And it's free for us too!! Nothing really bad about this program so far but maybe some new things could be added in future versions? We are using gree caht as an customer service tool right now because there is no other option out here (in my country).
The only thing i dislike sometimes when chatting through google chrome browser is how fast you get disconnected from your conversation partner if he doesn't see what u're typing immediately after sending him something via message box.. It would help solving such problems by adding delay feature between messages sent & received.