In Storm, since it was a Drupal 6 based approach, all of the additional data for the various node types was stored in custom tables. This requires that custom form elements be added to the node edit form. The Field API will allow the use of widgets supplied by other modules, cutting down on the amount of code that must be developed for this module. It will also take care of storage and versioning. And provides built in views integration. On the developer side of things it will allow us to take advantage of some new Drupal 7 niceties like the EntityFieldQuery.
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