Now too bad but I'd say its "chat" functionality is pretty far from perfect for me.
The biggest question is: how about text encodings support? At this age, almost every IRC app got such support. Not all IRC channels are available in English ;)
I'd also would like to have text input field somehow integrated into the chat window. Of course all these drawers are cool but drawers are kind of for displaying information you want to see may be sometimes, definitely not all the time. Putting the text input field in a program created specially for typing text messages into a drawer seems a bit strange for me.
I'm staying with Conversation for the time being.