Waterfox is a web browser based on Mozilla's free and open source platform. This utility was created for power users who wish to have the liberty to customize their default web browser according to their needs and get access to advanced useful features.
Basically, Waterfox provides you with all Firefox features. It simply gives you access to extra attributes and eliminates the most common Firefox issues.
The application comes as an alternative to using Mac's default tool - Safari for browsing the web. Unlike most popular browsers, this utility gives you the ability to customize your browsing experience however you like it and prevents some of the most talked-about Mozilla issues (for example, data collection) from happening.
This program removes startup profiling, data collection, and sponsored tiles on New Tab page, allows you to run unsigned extensions, and disables Encrypted Media Extensions (EME). What's more, it brings you an additional tab option -> Duplicate Tab.
Hence, I can't find a single bad thing to say about this application. It's effective, feature-rich, and open source. You should definitely give it a try if you're looking for an alternative to using your default web browser.