Beside the difference in features regarding reading and listing existing posts, the APIs have different support for blog post properties. While some simple APIs only allow to define the text of a post, better ones allow to set the title and other ones also support extendet properties like date, date to publish, categories and other.
Once you have the driver object for your blog, you should get a list of post properties supported by your driver. The method is getSupportedPostProperties(); it returns an array of property names. Currently, the following properties are possible:
See the API documentation of Services_Blogging_Post for the data types.