One browser that I think is promising for power users is Nyxt. It's designed to support multiple browser back-ends with Webkit currently supported and Blink under experimental support. Nyxt also includes out of the box support for Vim, Emacs, and CUA keybindings for keyboard-centric navigation. The fact that is can also be extended and configured with Common Lisp makes it feel like the Emacs of web browsers. The only reason I haven't switched to it yet is that it doesn't include support for WebExtensions yet, but it's a planned feature.