The Pros and Cons of ReviewBoard.

[Eric Snow]

Given that I've in some part driven the switch to ReviewBoard, I want
to make sure we are all on the same page and any decision on its
future can be made objectively.  This is an outgrowth of the current
discussion on whether or not we should ditch reviewboard.

Let's look at the pros and cons of using it (at least relative to
github).  Feel free to expand on any point here or add to them.

-eric

ReviewBoard Pros:

* self-hosted (flexibility, ownership)
* unified review queue with detailed info
* reviews are composed of multiple comments, not just one
* reviews have worklow-supporting metadata (ship-it, issues)
* reviews can be edited as a whole before publishing
* review comments are threaded (provides context)
* customizable (3rd party and custom extensions)
* extensive remote API
* some github integration
* supports chained branches (anti-pattern?)
* allows you to look at new changes in context of old comments
* allows you to look at changes between review request updates
* does not require a PR to exist

ReviewBoard Cons:

* self-hosted (hosting, maintenance, etc.)
* adds manual steps to our workflow
* extra steps increase the barrier to contributing
* not a part of the mainstream github workflow
* requires adjusting to a new tool for most people
* web UI has some usability issues (list?)
* emails formatting is complicated (subjective)