Within the framework of the European Network of Excellence on Antennas ACE, in 2005 the working group on software initiated a benchmarking action. At the Katholieke Universiteit Leuven this lead to a thorough investigation of six simulation tools, five well-known commercial ones and one in-house developed. They were confronted with each other for four different antennas. Two of these antennas can be considered "small antennas". It is crucial to point out that all possible efforts have been done to guarantee the most optimal use of each of the software packages, to study in detail any discrepancies between the solvers, and to assess the remaining simulation challenges. The study clearly highlights the importance of understanding EM simulation principles and their inherent limitations.