When i was there - Codeflow had the following feature
- Multiple reviewer states ... accepted/reviewing/awaiting changes/decline to review/reject change. - Multiple comment states ... pending, won't fix, fixed etc. - Iterations based code review flow - after you review - you come back easily view the next iteration (relative diff) - you can really compare back and forth and track comments through iterations - github tends to loose comments through commits - Support for bots to comment like stylecop etc
Codeflow workflow felt like an MS-Office application like Word or Outlook compared to Github - Heavy UI based workflow with no API/commandline counterpart sometimes - Desktop app - not website - Lots of knobs/states - Very easy to work back and forth in the UX
I agree with an earlier comment however - the UX was pretty ugly - the workflow account for lots of states Github doesn't but there is a nice linear flow to the progression of a github conversion that (at least at the time i was there) . IIRC it was a managed .NET - WPF application which are kindy clunky - not as nice as a website with clear links etc.