Like we all know both messengers are highly recommended for users with more then one instant messengers installed on their system. Both messengers have their own positive and negative points at which you should look carefully before you start using one. Messenger 2 has great extra function like Video chat, Audio chat and peer 2 peer filesharing which are all very usefull and most wanted for most people. Trillian has no such options in the basic version, not even in the Professional version. But you never know what Cerulean Studios will introduce in their next upcoming Trillian 3 Proffesional version. Read the comparison by following the link.