To face to the complexity of the system structures, both dynamic and stationary grouping models have been recently developed for the maintenance of the systems with complex structure. In order to support the maintenance manager in making a good choice of the maintenance strategy, this paper focuses on the qualitative and quantitative comparisons of the two above grouping models (dynamic and stationary). The qualitative comparison is done according to the dynamicity of the grouping planning, the difficulty in maintenance management and organization and the complexity of the maintenance modeling and maintenance optimization. Meanwhile, the quantitative comparison pays attention to the performance of the considered grouping models. To this end, the dynamic and stationary grouping strategies are firstly applied for the long-term maintenance planning of a substation automation system containing 11 components. The quantitative comparison is then done by using the long-term expected maintenance cost rate criteria. The results obtained show that the dynamic grouping is more powerful than the stationary grouping. However, the implementation, the maintenance modeling and the maintenance optimization of the dynamic grouping are usually more complex in compared to the stationary grouping.