I was wandering the tubes, as I do, and came across Vivaldi. It's from some people who used to work on Opera, but uses Chromium as its base (which means it can use at least most Chromium extensions).
The little I've played with it, the interface is great. It's not as fast as Firefox post-update, but hopefully they also aren't in a hurry to force advertising into the browser, either. Vivaldi does some neat things with tabs (like allowing tab groups that you can then open side-by-side in one window), as well as allowing smaller feed-like windows to one side, and text notes.
PCWorld did a more thorough review, and I haven't been using it very long. Still, it's something I'm going to be playing with for awhile, as I'm really enjoying what I'm seeing so far. (I have had to change some keyboard shortcuts to their Mozilla-like counterparts, but that wasn't hard).
I used it for Mac for a little while. I have a gimped Macbook Air and I thought it was a resource hog so I switched to Opera which is probably no better. Every program seems to just take up a shit load of available RAM. So I don't know