On the whole it is a huge improvement (thanks for all your work on this, Chad & Daniel): - finally one can navigate from the global comment to the inline comments (although I wish they would stand out more in the history list) - the super annoying bug where clicking anywhere on an old page with no/different CSRF token would log you out is gone - related commit list is nice (although it would be more useful if the topic could be changed after the commit was merged, but I suppose it is stored inside the commit itself so that's not possible) - the personalisable "My" menu is very handy - including the commit hook setup in the clone command is a nice convenience - as others said before, merge status and inline editing are cool - some of the new search options look very interesting (conflicts:, is:mergeable, project prefix, commit size). And file search just works ( https://phabricator.wikimedia.org/T63463 is not needed), yay!
Some of the navigation changes are for the worse (hiding PS lists/download links, new diff header) but not a big deal. Lack of wrapping is going to be a major pain point though, as others have noted.