Here are some screenshots of our new feature. After the review period is concluded, students can compare the reviews they wrote, with the reviews written by other students for the same homework submissions. In this way, students can see if they were accurate in their reviews, and they can see how helpful they were compared to the other reviewers.
We are considering letting students compare reviews even before the review period is concluded -- the idea would be to let this be at the discretion of the instructor, rather than forced for all assignments. Technically, this is an easy feature to add. The pro is that this would allow a real discussion to take place on homework submissions. The cons is that some lazy students could decide to enter blank reviews, and wait until their fellow students do their reviews to copy the gist from them, with a bit of cosmetic modification. Perhaps saving both the initial review, and the final one, would be deterrent enough.
In the meantime, here are some screenshots of the new feature.