1. In Gitlab, after you get +2, you can still commit changes and merge. Gerrit will make sure that you seek +2 again on the new set of commits. 2. Gerrit allows you to create draft comments on review and submit all comments in one shot after u reveiew them. 3. Require +2 rather then two +1 is a very interesting idea in Gerrit
There is a setting in GitLab to have people approve again after you change the merge request.