As the SP-API is relatively new, the data sets are very much in motion. The SP-API is an improvement over the MWS API as we are now able to access VC Retail Analytics Data, and other Seller Central data, such as business reports data, all of which have been ongoing pain points for our users.
Amazon has been actively testing Beta data sets (such as, at time of writing, SC Brand Analytics), which being in Beta has yet to be released through the SP-API. As things move fast in the Amazon world, please contact us for the latest information on data set availability.