Oh dear god. This post alone is enough to make me want to leave the forums and never come back. Please tell me you are kidding.
I have had to put up with every mail system there every was at some time or another, but nothing gets an entire userbase as angry as that useless piece of sh*t. Every place I have ever work that used cc:mail or notes - EVERY user wanted to change (even the IT departments). People would sit around and discuss how slow and useless it was from a user's point of view at cofee machines, meetings, dinners! ARGH!
The only nice thing I can say about notes is I like it's searching capability.
Most places I worked that migrated away from it, had instantly happy employees on the day that the new mail system was turned on.
Anyway. Rant over.