Somehow, (and I should whip myself for it), I forgot about the total lack of security in Clearcase. Someday there will be a Windows-worm that contains an optional Clearcase vector that either corrupts files or replaces executable content (and/or makefiles), and it will decimate companies it gets inside. Open network shares and I can edit anyone's files on the network. *Not* cool.
I suppose it hasn't stung me yet, but unless Clearcase is forced on you, that's reason enough to avoid it. (But anyway, other than the leaking airplane gas tank (please ignore that gaping hole in the wing!), it flies well enough).