The developers of DMDirc say they were motivated by a need to develop a truly decent IRC client for Linux.
Fortunately for Windows users, they decided to base it on Java meaning this works across both platforms - in fact any that runs Java. The program works by listing all the available IRC servers on the left hand side of the very simple interface including the name of each channel. On the right side, you have a compilation of all the aliases that are available. That's about all there is to it, which is good in that it's extremely simple, but bad in that it's also extremely limited. There are no options of conference chats, video conferencing or sending files which are basic in most IRC clients. About the most customization you can do is change the colour and fonts of the text plus a few more simple commands which are available through the help command. That said, the program is going though rapid evolution and development at the moment and it now features new launchers which give the client the ability to update itself via the updater, a URL Handler which allows adding support for non-http links and a much improved plugin system.
Very basic although easy to use, this is probably more attractive to Linux users than Windows fans.