Opera's Speed Dial (new tab page) has the ability to hold as many websites as you want, and you can customize it almost however you want. You can also organize the websites on the Speed Dial into folders.

It doesn't consume much RAM, unlike Chrome.

Scores top on Basemark.

The built-In adblocker is faster than any extension. It's possible to add your own filter lists. However, the adblocker isn't enabled by default.

Unlike other browsers, you can install add-ons such as tabs, bookmarks, history, sessions, notes, and extension manager in the sidebar. So you have the flexibility to use it for your purpose.

Free and fast VPN onboard, includes Germany, Canada, USA, Netherlands, Singapore.

You can pop-out any video and it will stay on top while you are surfing on other tabs.

Since Opera is built on Blink, the same engine Chromium is built on, it was possible for Opera developers to allow Chrome extensions to run in their browser.

Opera scores highly on HTML5 feature support.

Opera Sync allows you to synchronize your bookmarks, passwords, and more from any computer, phone, or tablet.

Opera is full of user controlled settings. Everything can be imported and exported even RSS feeds. It can be skinned in a variety of different themes or it can be extended through the use of a large number of plugins available.

Opera supports cross-browser extensions. Opera Addons site keeps quality up compared to Chrome Store. Full of useful extensions, Opera also supports extra APIs like Speed Dial API, Extension Sidebar API and Stash API meaning wider variety of extension possibilities than in Chrome.

Just highlight price on a website and see this price in your currency.

You can save the Opera's setup files on a USB hard drive and run its portable version anywhere.

Source code available on GitHub.

Opera has a functionality called Turbo which increases browsers speed and reduces data consumption considerably by compressing the data that's found in a web page.