UAV surveys have become more and more popular over the last few years, driven by manufacturers and software suppliers who promise high accuracy at low cost. But, what are the real possibilities offered by this kind of sensor? In this article, we investigate in detail the possibilities offered by photogrammetric UAV mapping solutions through numerous practical experiments and compare them to a reference high grade LiDAR-Photogrammetric acquisition. This paper first focuses on aerial triangulation and dense matching accuracy comparison of different data acquisition units (2 types of camera) and processing softwares (1 open source and 2 proprietary softwares). Finally, the opportunities offered by these different approaches are studied in detail on standard aerial applications such as power lines detection, forest and urban areas mapping, in comparison with our reference dataset.