In May (weekend of the 4th and 5th) Firefox had a problem that broke almost of their extensions. I am a heavy user of those extensions. The loss of those extensions broke the internet for me. It left me using Chrome and Chromium, which isn't bad, but it's not what I prefer.
So, I decided to give Waterfox, a fork of Firefox, a try!
I also said that I'd give you all an update on my experiences with various browsers. I've been using Waterfox as a daily browser since May and I love it. It behaves exactly like Firefox and I'm able to use all of my lovely extensions. Some of the extensions take a bit of fiddling, but if you aren't a power user, you probably won't need to.
One of the nice things about Waterfox is the lack of corporate apps included on install. There's no Pocket.
I like it because it lends itself to choice and risk. It doesn't tell you what you are allowed to do because you will be taking a risk. I can easily install extensions and plug-ins that are not on the Firefox white-list. Waterfox treats you like a grown-up.
In addition to the extensions available at the Mozilla site, Waterfox maintains a collection of archived addons.
The devs are responsive and have a subReddit for support. They post frequently on their blog.
Waterfox is available for Windows, Mac and Linux.
All in all, it's a great substitute for Firefox.