Peer review is generally regarded as a useful learning tool for students, providing them with opportunities to interact with their peers when engaging in the process of critical reading and critical thinking, thus possibly raising students' motivation to learn. For peer review to be a manageable task for students, appropriate scaffolding is believed to be pivotal. The present study mainly aims to investigate: 1) how students at two levels of English proficiency will perceive the usefulness of the peer review exercise completed; and 2) whether the scaffolding provided to them is viewed as useful and the reasons behind. The participants involved 76 university students taking two academic writing courses at a university in Hong Kong. Quantitative and qualitative data were analyzed collectively for the responses to an online anonymous questionnaire. Both groups showed favourable responses to the peer review exercise, including the preference for the retention of the peer review exercise. Several findings, however, differentiated the two groups, e.g., significantly a greater number of higher-ability participants than did the lower-ability students agreed to the benefit of peer review with respect to: a) writing a thesis statement; b) using hedges; c) using in-text citation; and d) building friendship. [This paper was published in "English Language Teaching and Linguistics Studies" v5 n4 p180-205 2023. The paper was presented at The 11th European Conference on Arts & Humanities (ECAH2023), Iafor (17 July 2023), University of London, London. Hybrid mode.]