I've used the DITA-XML Learning and Training specialization to write technical training documentation and I loved it. So much flexibility in generating document outputs and customizable standardisation.

Choosing the right information model for your company/group is not an easy task, but it's not the main hurdle. The major problem we had adopting DITA was having managers understand the added value of taking the time to train people to understand and write structured documentation.

I'm in a new job in a bigger org and I'm trying to show them the benefits, but that boat is really hard to steer. People REALLY like the WYSIWYG freeform documents.