Well-structured transitions systems (WSTS) are a general class of infinite state systems for which decidability results rely on the existence of a well-quasi-ordering that is compatible with the transitions. Many models can be seen as WSTS : lossy counter machines, lossy channel systems, string rewrite systems are for example WSTS. Petri Nets are another famous model that can be seen as a WSTS. Since the introduction of Petri nets, many extensions have been proposed, most of them being well-structured. One of the recent ones are data nets, that subsumes almost all already proposed extensions. The focus of our work was to try to find the limits of data nets, and to try to distinguish them from other extensions. As a secondary goal, we wanted to provide an alternate representation of data nets to ease the comprehension of this model.