The concept of powerful and simple code navigation can be mind blowing for productivity. While modern editors have become slicker, I think that many have lost the customisation from macros that made it so easy for emacs users to create their own productivity workflows. Never the less, I will try sourcegraph.
Fun fact: both Quinn and I (Sourcegraph cofounders) still use Emacs as our primary editor :)
(But frankly, all other editors except Vim are great, too :P)