Node content versioning and compare tool I already know that node content versioning is supported in drupal, what I want to know is how much?

I for instance create a content type 'article' and add some extra text fields to it, The article content should have the capability to be reviewed and altered by many authors/reviewers and their changes will be saved as seperate records not impacting the real article record, only if I approve their changes will they be reflected on main article record.

Which of the functionality is currently supported and what is not?

Thanks
You can use Revisioning module for comparisons of different revisions:


  Revisioning is a module for the configuration of workflows to create,
  moderate and publish content revisions.


or you can use Diff module:


  This module adds a tab for sufficiently permissioned users. The tab
  shows all revisions like standard Drupal but it also allows pretty
  viewing of all added/changed/deleted words between revisions.