There are two Telepathy connection managers that support MSN: Butterfly, which is an MSN-specific CM built on pymsn, and Haze, which uses libpurple. Prior to libpurple 2.5.0, Haze's MSN support was rudimentary, but libpurple 2.5.0 and newer reduce the gap between Haze and Butterfly considerably. Still, you will probably have a better experience if you use Butterfly.
Features unique to Butterfly
- Support for multi-user conversations.
Features unique to Haze's MSN support
- (none at the moment)
Features previously unique to one or the other
- Setting aliases for your contacts, which are saved on the server (libpurple 2.5.0 adds support for this to Haze)
- Avatars for others and for yourself (although Empathy breaks this in Haze)
If you have both Haze and Butterfly installed, Empathy will only offer to use Butterfly for MSN accounts. If Butterfly is not installed, it will offer an "MSN (Haze)" protocol as a fallback.