Which structure format is best for user guides and why?

I use Framemaker 7.2 structured to generate software user guides.

Currently I am trying out Framemaker 10. In the Structure folder of the Framemaker installation folder there are many different types of structures available. The XML - UserGuide structure looks nice, but does not have elements for note or warning boxes.

In general, which of these out of the box structures (found in C:\Program Files (x86)\Adobe\AdobeFrameMaker10\Structure) are advisable to take for user guides? and why? what advantages does each structure (Book, DITA, xdocbook, Online, etc.) bring?

I would be grateful for any help you can provide.