The WritePoint staff blog makes a very good point about DITA: it isn’t a magic wand that fixes documentation problems. Also, it’s worth noting that:
… DITA didn’t introduce something completely new. DITA incorporates achievements made in a wide variety of approaches to organizing content that were being proactively conducted starting from 1960’s.
Don’t get me wrong: DITA can be a good solution for many departments that want to set up an XML-based single-sourcing environment. Just don’t expect that a twitch of your nose will convert your legacy content or make the output from the Open Toolkit match your formatting requirements.