When comparing DuckDuckGo vs Dolphin, the Slant community recommends DuckDuckGo for most people. In the question“What are the best Android web browsers?” DuckDuckGo is ranked 15th while Dolphin is ranked 18th. The most important reason people chose DuckDuckGo is:
DuckDuckGo does not collect or share any personal information. Their [privacy page][1] has a great rundown on why privacy is important. The most important repercussion of this is that DDG doesn't use the data collected to tailor results, avoiding exposure to the "[Filter Bubble][2]". [1]: https://duckduckgo.com/privacy [2]: http://en.wikipedia.org/wiki/Filter_bubble
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Very protective of user privacy
DuckDuckGo does not collect or share any personal information. Their privacy page has a great rundown on why privacy is important. The most important repercussion of this is that DDG doesn't use the data collected to tailor results, avoiding exposure to the "Filter Bubble".
Pro Infinite scroll of search results
DuckDuckGo results page is an infinite scrolling page, so you don't need to be clicking through pages.
Pro Ads are non-obstructive and don't track you
The ads are clearly labelled as ads and are non-obstructive. The ads are based on the searched keywords and there's no tracking involved on their visibility. You just need to remember that the site the ad links to might track you.
Pro Can disable advertisements
The search engine allows freely disabling ads.
Pro Allows searching from specific sites using bangs
Bangs are commands that allow searching via a different website's local search engine, using keywords or abbreviations with an exclamation mark (!). For example searching "world war ii !wiki" will automatically redirect to Wikipedia.org and show results for the query "world war ii" there, instead of DuckDuckGo, using Wikipedia's search engine.
The more common sites have shortened alternatives for these commands. Such as !g for Google, !i for images and !yt Youtube.
The whole list of bangs can be found by typing "!bang" in DuckDuckGo.
Pro Has a wide spectrum of instant answers
For select queries DDG pops up a box that supplies the exact answer. For example, searching "stopwatch" will pop up a stopwatch, asking for "words like..." will show a list of related words, typing "password" will generate a password, etc.
Pro Many customization options for appearance
DDG allows customizing almost any aspect of the search engine's appearance including fonts, page width, alignment, header behavior, site icons, etc and has a selection of premade themes available as well.
Pro Lets you watch YouTube videos from the site
Duckduckgo lets you watch videos right from their site, so you can have more privacy than watching on youtube.com.
Pro Has a .onion site
Only accessible from Tor.

Pro Sometimes results are better than Google
Sometimes the search results are better. Most of the times, they're at least as good as.
Pro Has many fun features
For example, if you search "Color Picker" , you see a color picker.
Pro Can function without JavaScript
Of course, it's nicer when enabled, but it's not required. Some browsers are too limited (mobile, terminal) or turn it off for security reasons (tor, etc.), and DDG still works.
Pro Good for Linux users
DuckDuckGo has an API with some websites. With the help of this API, if you search for a fix of a problem in Linux, you can easily find an answer to the problem. For example, if you search for "How to update linux", you will get a message like this:
How to install updates via command line
Try this:
sudo apt-get update # Fetches the list of available updates
sudo apt-get upgrade # Strictly upgrades the current packages
sudo apt-get dist-upgrade # Installs updates (new ones)
--SirCharlo
Pro No filter bubble
DuckDuckGo does not filter your search’s with the data that they have. You get to see everything the Internet has to offer in a safe, private way.
Pro It's mainstream
This is the biggest private search engine there is
Pro Lets you go to other sites
You can go to the Wikipedia page for pigs by doing !w pig.
Pro Immenseley configurable
As with any KDE app, Dolphin, allows adding or modifying toolbar buttons and keyboard shortcuts.
Pro Can split views
Dolphin supports splitting the view in two navigational areas, this way you can navigate two different directories at the same time.
Pro Integrated terminal
Pressing F4 with any opened folder on a mounted path opens a console within dolphin.
Pro Also has a refresh option
Dolphin is without a doubt the best fully functional and easy to use and multitask with.
Dolphin also has a refresh button which no other File manager has. It's great for tracking a large files transfer; that's what file managers are for - good common sense.
Pro Easy to extend with plugins
Dolphin follows KDE's philosophy of being extendable and configurable. It can easily be configured and customized through plugins.
Pro Auto mounts flash drives
Dolphin automatically identifies and mounts external flash drives.
Pro Fast at opening graphics folders
Pictures with or without previews is optional and selectable at the touch of a button.
Pro Does not use third party libraries
Unlike all those GTK-based file managers it does not have to rely on external written software for its functionality because KF5 is KDE SOftware and developed alongside.
Pro Keeps its state
It starts with last opened folders.

Pro Fully supports HiDPI
Supports HiDPI displays.
Pro Automatically centers items
In icons view mode, the space between files gets stretched so that there is never and annoying empty space at the right side of the window.
Cons
Con No date information in search results
In search results, there are no dates when the pages were published, which doesn't allow you to immediately know if the page is outdated.
Con Downranks misinformation results
Company announced that they are downranking misinformation results about the war by Russia media, after Russian's invasion of Ukraine.
Con Irrelevant search results
They store no information about you (theoretically a pro) but this results in absolutely awful search results, and having to modify your search terms 4-5 times to get what you are looking for.
Con Owner would compromise his service/customer privacy
In a question to Weinberg, “if you were served an NSL or were commanded to compromise your service/customer privacy in any way, would you and could you just pull the plug like Lavabit did or would you run into opposition from shareholders/investors that would prevent you from doing so?” Gabriel Weinberg said: “No one is preventing me from doing that.”

Con Still not better than Google
Results are quite often not as good. They just lack resources to do it, for now.
Con Based in US, so they cannot guarantee there is no backdoor
Con DuckDuckGo has no 3rd party certifications
Con Activism censorship
They started to block results based on activism.
Con Search using language other than English is not so great
Korean would never use it.
Con Referrers
A referrer is an HTTP header field that identifies the address of the webpage (i.e. the URI or IRI) that linked to the resource being requested. By checking the referrer, the new webpage can see where the request originated.” Basically it tells a website where you came from. DDG does give this out.
Con Bing = DuckDuckGo
Duckduckgo depends on Bing for the query.
Con Search results are often unrelated and limited
Common conversions do not work, i.e. searching for 15F to C does not give you the conversion but just a bunch of conversion websites. Very frustrating. It's a simple thing but makes a huge difference to the browsing/searching experience. Also location based only works for the country you're in. Searching for, say, McDonalds only gives country results for McDonalds and no local results such as where a local restaurant may be. Not very helpful.
Con DuckDuckGo has many 'Owners'
DuckDuckGo is owned by Gabriel Weinberg who is is the founder, current CEO and controlling shareholder. Investors/shareholders include Union Square Ventures and several others. DuckDuckGo generates its income from advertising (Bing Ads) and collects affiliate revenue (Amazon, eBay).

Con Needs a clearer vision of the future
What's duck's goal or quest?
Con Shows too few images
When searching for images only, it shows too few of them and only a handful are related to the search terms.
Con Hosted on Amazon servers (EC2)
Con Bangs do not protect user privacy and can be misleading
Using these bangs will instantly connect you to the service you requested. For example typing “!g white cat with green eyes” and hitting return, drops you off on the Google website to display your results (thus logging your IP, search term and browser info immediately). It does not get you Google results inside DuckDuckGo. It is reasonable for DDG users to assume and expect a private search engine warns if there is a risk to that privacy being lost, like it does with Youtube videos but in the case of Bangs this does not happen.
Con Saving settings in Duckduckgo's Cloud still needs improvement
Cloud save and the ability to pull up your settings on any device is a nice idea but the implementation needs work.
Con Doesn't do personalized searches
Since they don't track you the results are not tailored to your interests.
Con Form over function (overall search experience is poor)
It's nice to adjust the settings and all but after a couple of days you will want to go back to a more functional search engine.
Sure DDG looks shiny and !bangs are great but many wouldn't consider it as a viable alternative. Better results for search queries is more important than fancy looking CSS.
Con May be a little slow on startup
Dolphin can be a little slow on startup (depending on distro, hardware etc...). Startup time can vary from a couple of seconds to up to a minute.
Con Can hang on remote file systems
It doesn't cope well with remote file system nicely like sshfs or any samba, like when network is not responding/very slow. It just hangs.
Con "Type" column too verbose
Despite having a large enough monitor, if you keep the size of the browser window small, the "Type" column (in "Details" view mode) insists on including the complete multipart MIME string, making the column so wide that trying to limit its width makes the column useless. Sorting by "Type" renders the list into an incomprehensible mess.
Con Poor optimization on later versions
Con Too simple
Feels weird on KDE because it has less customizing options Konqueror and any other KDE app have.
Con Can't perform ROOT actions
Developers set a constraint in Dolphin that deny Dolphin to run with root permissions. Hence, if you want to perform an action that require root permissions, such as rename a file in /etc/ folder, you are forced to use terminal or switch to another file manager.
