Vivaldi is a feature-rich and nicely designed application that comes as an alternative to using Safari, Mac's default Web browser, for checking what's new on the Internet. This program provides you with various options for customizing the appearance of its interface, has features that address to color blind users, allows you to write notes, and so much more.
Its default page arrangement looks a lot like the interfaces of other Mac browsers. The difference is that you can customize the appearance of this browser however you like. For instance, you can change the position of the address bar, move all tabs to the bottom of the main window, etc.
Another important advantage is the fact that it comes with a notes panel where you can write project ideas, reminders, and many others. You can use a certain key combination to reveal this notes panel (it's listed in Preferences -> Keyboard along with many other shortcut keys).
I also like that the browser adapts its theme based on the page you're visiting. For example, if you log in to your Facebook account, the main window of the interface becomes blue.
The program gives you access to plenty of other useful features, like the ability to surf incognito, access to a powerful bookmark manager, etc.
With that being said, I'd say it's worth trying Vivaldi if you want to switch from your default Web browser to a new feature-rich tool.