When comparing Opera vs Chromium, the Slant community recommends Chromium for most people. In the question“What are the best desktop web browsers?” Chromium is ranked 6th while Opera is ranked 7th. The most important reason people chose Chromium is:
Unlike Google Chrome, Chromium is completely open source.
Ranked in these QuestionsQuestion Ranking
Pro AdBlocker onboard
It's possible to add own filter lists. The internal adblocker is faster than any external.
Pro Compatible with Chrome extensions
Since Opera is built on WebKit, the same engine Chrome (among other browsers) is built on, it was possible for Opera developers to allow Chrome extensions to run in their browser.
Pro Video pop-out feature
You can pop-out any video and it will stay on top while you are surfing on other tabs.
Pro VPN onboard
Free and fast VPN onboard, includes Germany, Canada, USA, Netherlands, Singapore.
Pro Opera Turbo
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.
Pro Strong HTML5 feature support
Opera scores highly on HTML5 feature support.
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.
Pro Battery saving mode
Pro Opera Sync
Opera Sync allows you to synchronize your bookmarks, passwords, and more from any computer, phone, or tablet.
Pro You can install extensions on the sidebar
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.
Pro Opera can have extensions from Opera Addons & Chrome Store websites
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.
Pro Speed Dial
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.
Pro Partly open source
Source code available on GitHub.
You can save the Opera's setup files on a USB hard drive and run its portable version anywhere.
Pro For Opera 2017 & 2018 gonna be time of new
Opera got Reborn UI as the first implementation from Opera Neon concept browser. Snap -feature is next. Opera constantly improves its basic functionality - unlike Chrome.
Pro Blazingly fast
Scores top on Basemark.
Pro Fast video loading
Opera loads videos faster, making it useful for slow internet connections.
Pro Completely open source
Unlike Google Chrome, Chromium is completely open source.
Pro Supports all of Google Chrome features
As Chrome is based on Chromium they overlap in supported features. Chromium syncs between devices, automatically updates, has great built-in developer tools, installs extensions without a restart, includes a combined text bar for entering URLs and searching and has excellent HTML5 compatibility just like Chrome.
Chrome and Chromium are available on almost every device nowadays
Pro Access to Chrome's extensions
Chromium can access the Chrome Web Store and all the extensions hosted there can be installed and used on Chromium.
Every tab and plugin runs in its own subprocess so they will never affect the whole browser ,however that consumes more memory than other browsers
Pro Backed by Google
Chromium was first released as a large portion of Chrome's source code as an open source project by Google in september 2008. The idea was to encourage developers to review the underlying code and to contribute in making Chrome cross platform and port it to Mac and Linux as well.
Nowadays Chromium is a large project with a huge community that's standing behind it but still Google continues to take an extremely active role in Chromium development. This ensures the longevity and constant development and improvement of the browser.
Con WebKit/Blink is not customisable or lightweight
Opera is built on WebKit/Blink, which means it shares cons of Chromium: high RAM usage (Not lightweight), lack of customizability.
Con Cannot select tabs
Unlike in Chrome and Vivaldi, one cannot select multiple tabs to move to another/new window.
Con Opera is owned by a Chinese Consortium
Who certainly need to conform with Chinese government requirements to let them infiltrate everything you do online…
Con Uneditable default search providers
It can not delete or replace already built-in search services such as Yahoo, Google, DuckDuckGo, and Wikipedia.
Con Fewer extensions
Con Extension icons not directly moveable
Con Basically a Chrome clone
The latest versions of Opera are basically Chrome clones, so they really don't add anything new.
While Opera is currently available gratis (without monetary charge), it is currently not libre (meaning that it does not allow users to view the source code used to create, to modify that code, or to redistribute modifications) and is therefor neither free nor open-source software.
Some buggy or confusing behavior with the bookmarks bar and moving tabs, and entire windows turning black after a while.
Con High RAM usage
Just like Chrome, Chromium also eats a lot of RAM, which can be a problem for machines with smaller RAM.
Con Lacks privacy options
Con Lacks support for certain common media formats
As Chromium avoids bundling any proprietary software, media that requires proprietary codecs or formats such as AAC, H.264, MP3 and Flash will not play by default on Chromium.
Con Simple, dull, bare-boned
Con Misses some proprietary multimedia codecs
Unlike chrome, Chromium misses proprietary multimedia codecs per default. There might be some ways over ffmpeg and co but it is still a gray zone. Also by enabling, it also removes one of the core features of Chromium of being open source software
Con No official builds
There are no official builds available so you have to rely on a third party distributor
Con Doesn't read cookies properly
... and for this reason it only remembers the user logins only in the session. Once the browser is restarted for whatever reason, it forgets everything and the user has to login again everywhere which can become annoying very quickly.