The key philosophical difference is that in Gerrit you are proposing a specific change, where in GitHub you are proposing a branch be merged. It's a very subtl

The key philosophical difference is that in Gerrit you are proposing a specific change, where in GitHub you are proposing a branch be merged. It's a very subtle distinction, but having worked on OpenStack in the past, I much prefer the Gerrit model. Patch revisions are much easier to track over time than pushes to a PR branch during review.