Adium has for a long time been the best multi-protocol IM app for Mac. But unfortunately, the latest versions are, for the most part, broken. Version 1.3.1 has had MSN support working, but the library, used for MSN protocol, has had its internal debugging messages enabled, which would generate thousands of messages in system logs (and which would, consequentially, prevent Apple laptops from sleeping, since they won't automatically go to sleep mode if there's any disk activity going on).

Version 1.3.2 switches to a new MSN support library, which - surprise! - breaks Live Communication service compatibility, so no contacts, created on a private Live Communicator server (for example your company's internal server) will ever show up, and the Adium will bombard you with messages each time it connects to MSN about whether or not you'd like to add a new contact (which will not show up as available even if you say "Yes").

The bug report has been created over 3 months ago, while 1.3.2 was still in its beta stages, and then 1.3.2 was release, with the bug still in it.

It sucks to have to switch away from such a great application, and I really hope the Adium developer team is going to fix it soon.

If you, however, don't care much about MSN support - then sure, Adium is the best IM client for Mac.