We report on a study comparing peer feedback with feedback written by tutors on a large, undergraduate software engineering programming class. Feedback generated by peers is generally held to be of lower quality to feedback from experienced tutors, and this study sought to explore the extent and nature of this difference. We looked at how seriously peers undertook the reviewing task, differences in the level of detail in feedback comments and differences with respect to tone (whether comments were positive, negative or neutral, offered advice or addressed the author personally). Peer feedback was also compared by academic standing, and by gender. We found that, while tutors wrote longer comments than peers and gave more specific feedback, in other important respects (such as offering advice) the differences were not significant.