Update: After a reboot I have gotten Fring to work correctly, initiating MSN IM sessions as well as receiving them, no problem. And it allows you to type messages on the main chat window, just like the real MSN and unlike Eqo and Mig33.
Its interface is entirely lackluster and has no options to do anything but send messages. You can't change your status, add new contacts, or even log on or off during a session - you have to exit the entire program to go offline.
That said, it does work and do what it's supposed to do, so hey, I'll take it for the moment. Thanks!