Every WM will have a report in the following format:
Imaginary Window Manager (IWM)
A beautiful screenshot of a Window Manager that doesn't actually exist ...
Version of the WM I used. Also a listing of the most recent version available at the time of writing, and when it was published.
How good is the documentation?
Is it themeable? How much so?
My opinions of and experiences with the WM.
Positive things about the WM.
Negative things about the WM.
Whether or not there's a community around the WM, how active it is. Since I'm not a member of any of these communities, my guess at the level of activity is partly speculation. My best indicators are mailing list archives showing recent activity. Development, themes and IRC channels are other indicators, although not as strong.