No, ClIRC is the definite choice, as the others have an ugly interface, less features, lack proper configuration options, and do not offer the necessary basic commands I would expect from an IRC client. Can't go wrong with ClIRC.
Also, as long as you don't get too involved in the conversation, the keyboard is somewhat decent. The main issue is the small screen, but meh, that's about as good as the DS can get, and it's easier to use than phones or other consoles which do not offer a touch screen. It's good enough.