This study investigates the use of face-to-face and computer-mediated peer review in an English as a Foreign Language (EFL) writing course to examine how different interaction modes affect comment categories, students' revisions, and their perceptions of peer feedback. The participants were an intact class of 13 students at a Taiwanese university. The computer-mediated peer review involved "OnlineMeeting," software specifically designed for peer review activities and featuring a split screen protocol, document sharing, and chat room functions. The results of chi-square tests show that overall students offered more revision-oriented comments than non-revision-oriented ones among different writing tasks in either mode. Also, peer review mode affected some types of peer comments to a certain extent. There were significantly more global alteration comments and fewer local alteration comments in face-to-face than computer-mediated mode. While the participants liked comments via "Word's" annotation features over handwritten comments, they felt face-to-face discussions to be more effective than online chat via "OnlineMeeting" due to the affordance of face-to-face talk (e.g., immediacy and paralinguistic features), that cannot be easily replaced by electronic chat. Pedagogical implications regarding the balanced use of computer-mediated and non-computer-mediated writing activities are discussed, along with suggestions for future research.