Nielsen’s usability heuristics are the most recognized assessment tool to conduct heuristic evaluations. However, in a previous study we demonstrated these principles fail to cover all aspects of usability in the emerging categories of software products. The current generation of applications is embedded of special features that are not considered by the conventional principles. For this reason, we have developed a new set of usability heuristics that provide accurate results when are used to evaluate transactional Web applications. In this paper, we present a comparative study, in which the effectiveness of our new proposal and the Nielsen’s approach are contrasted. For this purpose, two groups of students were trained in a different set of principles. Subsequently, they were requested to conduct a heuristic evaluation using the approach that was assigned. Then, the results were compared. The analysis establishes that our new proposal covers more features, is more understandable and is perceived as easy to use. Although the promising results, some improvements and more experiments are required in other scenarios.