Gerrit, Reviewable and Phabricator are very similar, except that Critique is much more polished.
Having used all three, Gerrit works best and the new UI is starting to look pretty good. Reviewable has great UX, but inherits some of the disadvantages of GitHub PRs.
[1]: https://books.google.de/books/about/Software_Engineering_at_...
I think they kept the same keystrokes, though.
That is one nice thing about Critique is although it's a webapp you can drive it pretty much entirely by keyboard. It has the feel of an old usenet newsreader like nn, in a way.
But yeah... even I find the names difficult to handle and remember, even after using Phabricator for more than 4 years now. Nevertheless, it is a great piece of software, especially the code review process is top-notch.