When moving to structured authoring, DITA is working out to be less of a pain in the a** (PITA) than other options. The reason for this is that many of the tools have DITA support built in.

If you move to structured authoring and choose to make your own custom structure, there is set up you will need to do to get your tools publishing.  While all authoring tools require some kind of set up, I'll use FrameMaker as an example.  With a custom designed structure in FrameMaker, an EDD has to be created, the DTD or schema saved and adjusted, read/write rules written, and a Structured Application set up.  For DITA, FrameMaker's EDD, DTD, rules, and application are already built into the software.  So, with some tweaking of the FrameMaker DITA template (to look the way your docs are supposed to look) you can be up and running fairly quickly.

Once you create your DITA content from your tool, your DITA files or maps can be published pretty much immediately using what is freely available from the DITA Open Toolkit and sometimes from within the tool you are using.  Contrast that to a custom structure, which would require long hours creating XSLT or designing a proprietary publishing solution. 

With so many authoring tools supporting DITA, and so many freely available formatting scripts, moving to DITA can be faster and less painful than the same publishing might be with a custom structure.  Since tools from companies like JustSystems, ArborText, Vasont, Siberlogic, Idiom, and more support DITA you even have the ability to use multiple tools fairly quickly. So, if your content can fit the topic-oriented structure of DITA, it may be worth giving DITA a second look before your company develops something custom.

Kay