Is there any code review extension for Visual Studio 2013 professional + TFS as source control, for free, that already has community support or still under development?
Devart Review assistant is way better than code review tools built into VS and TFS. The most important feature that it has are iterative reviews - developers can add new changesets to the same review and restart it. And reviewer will still see his original comments, so he can check how they were addressed.
It is not free, but it is pretty cheap for small teams (10$ for 5 users).