It's a resource hog, crashes, it's constantly littering files all over SharePoint which becomes even more than a garbage bin than it already is.

And the UI is terrible, huge balloons around everything. I want density but even at the densest setting it sucks.

Oh and it also fails to update online status. Often I click on a colleague who seems green and only then it updates and it turns out they've been away for 3 hours. Grrr