The effects of peer assessment on students’ learning experience over time are scarcely examined in the literature. The current research performs a longitudinal study that explores the use of LearnEval, a comprehensive peer assessment platform, in two computer science courses in two consecutive years. Both courses followed a Project-Based Learning (PBL) approach, allowing a peer assessment component to be easily integrated. In 2020-2021 academic year, 78 students participated in the process in a 3$^{rd}$ year Web Applications Design course. In the following year, a subset of the same students (54) participated in the activity in a 4$^{th}$ year Human-Computer Interaction course. A quantitative analysis of the outcomes in the two years was performed and the results were compared. Furthermore, the LearnEval usability was assessed. Therefore, the current work addresses two research questions: (1) How do the outcomes of the peer assessment activity in the 4$^{th}$ year course compare to the previous year when the students attended the process for the first time? (2) How did the students perceive LearnEval usability in the two years? The main findings show that the results were slightly improved in the second year of attending the peer assessment process in terms of involvement, reviewing skills, grades assigned and quality of the feedback provided.