Theoretical calculations based on a micromagnetic approach describe the magnetization reversal in a uniaxial hard magnetic particle with surface defects and polyhedral shape by a few microstructural parameters. Nevertheless the application of these results to clusters of particles, e.g. melt-spun or sintered magnets, must be carried out carefully. Taking into consideration the distribution of the easy directions of the particle ensemble and the angular and temperature dependence of the microstructural parameters leads to an improved quantitative description of coercivity. Both, the influence of different degrees of texture and the angular dependence of the magnet orientation on coercivity can be explained. The effect of stray-field coupling is critically investigated by analysing remanence curves. To compare theoretical results with experimental data we prepared sintered magnets with a high degree of orientation as well as isotropic magnets and determined the temperature and angular dependence of the coercive field as well as of the remanence.