Gartner has recently released its 2019 Market Guide for Data Preparation ([1]), its fourth edition of a guide that was first published in the early days of the market, back in 2015 when Data Preparation was mostly intended to support self-service uses cases. Compared to Magic Quadrants, the Market Guide series generally covers early, mature, or smaller markets, with less detailed information about competitive positioning between vendors, but more information about the market itself and how it evolves over time.
While everyone's priority with these kinds of documents might be to check the vendor profiles (where you'll find Talend Data Preparation listed with a detailed profile), I would recommend focussing on the thought leadership and market analysis that the report provides. Customers should consider the commentary delivered by the authors, Ehtisham Zaidi and Sharat Menon, on how to successfully expand the reach and value of Data Preparation within their organization.