This paper presents a comparative study of compositional and annotative modeling approaches for software process lines. In our comparative study, Open UP and Scrum based software process lines extracted from existing projects are modeled and implemented using an existing compositional approach – EPF Composer, and an annotative approach – GenArch-P, with the main aim to address a systematic variability management and automatic process derivation. In order to promote the analysis of the approaches, some comparison criteria previously adopted in other studies were adapted. Our study results show that the annotative approach can bring many advantages to the modeling of software process lines considering our comparison criteria. On the other hand, our study also concludes that many existing compositional mechanisms should also be integrated with annotative approaches in order to improve the modularity of process elements associated to specific kinds of process variabilities.