What I really like about Phabricator as a review tool:
* keyboard shortcuts to navigate through the changes
* ability to add a comment to multiple lines of code
* ability to suggest changes inline
* comments are saved as I type them, so an accidental tab close saves my work
* comments are submitted in batches when I choose to, not one-by-one after saving each one. Its's sooo useful, because it often happens that I ask a question about some piece of code and upon further reading I find the answer, so I can delete the question before submitting all the comments and the author won't be bothered by it
If anyone knows of a feview tool with similiar set of features, please please let me know :)
When it comes to task management in Phab, I like how the tasks can be arranged in a dependency tree. We have our "todo" view set up so it only shows tasks without dependencies and sorted by prioroty, so the work on the project self-organizes