XML for document content (like, the whole point of markup) = awesome.

XML for app configuration or basic data transfer formats = horrible.

Unfortunately I fear so many people got burned by the latter issues they forgot (or missed entirely) all the greatness of the first.

P.S. Google has a bazillion dollars but can't figure out how to maintain a new secure XSLT library or update to a newer one which exists already? The usage argument is dumb…maybe a lot more sites would find good uses for XML/XSLT if this stuff was actually maintained and promoted properly!