When comparing i3 vs KDE, the Slant community recommends i3 for most people. In the question“What are the best window managers for Linux?” i3 is ranked 1st while KDE is ranked 26th. The most important reason people chose i3 is:
Every feature is thoroughly documented (including examples), and documentation is kept up-to-date. For questions that are not answered by the i3 [user guide](http://i3wm.org/docs/userguide.html), because they concern tools outside of i3 for example, there is the community [question & answer site](https://faq.i3wm.org/).
Ranked in these QuestionsQuestion Ranking
Pro Fully configurable (including tiling)
One of the biggest attractions of i3 is that it can be configured just about any way the user likes. Ranging from custom keyboard shortcuts to placement of opened apps, it is up to the user as to how they would like their window manager to behave.
Pro Easily readable plain-text configuration
i3 has plain-text configuration, meaning that no lua or haskell is needed. This makes it rather easy to recommend i3 to other people without worrying whether or not they have the knowledge to configure it as it can be read by anyone without prior knowledge.
Pro Easily switch to and manage floating windows
i3 can allow for the user to manage floating windows. Floating mode can be toggled by pressing $mod+Shift+Space. This way the user can take advantage of tiling as well as floating windows, all in the same session.
Pro Can tab windows
i3 permits tabbing through windows by turning on tab mode with $mod+w.
Pro Fast, especially on weaker hardware
Tiling means there are no fancy compositing or window effects to take up system resources.
Pro RandR support
RandR provides more information about your outputs and connected screens than Xinerama does. To be specific, the code which handled on-the-fly screen reconfiguration (meaning without restarting the X server) was a very messy heuristic approach and most of the time did not work correctly — that is just not possible with the limited information that Xinerama offers (just a list of screen resolutions and no identifiers for the screens or any additional information). Xinerama simply was not designed for dynamic configuration.
Pro Can stack
i3 allows for stacking of windows in its environment.
Pro Can be reloaded quickly and configured without a client restart
Just two hot keys: Shift+Super+C to reload the config and Shift+Super+R to restart (which takes less than one second). Restarts pick up new versions of i3 or the updated config file, so you can upgrade to a newer version or quickly see the changes to i3 without quitting your X session.
Pro No window gap
Space is not wasted by separators, therefore making the most of the confined space on smaller monitors.
Pro Sane development process
i3 uses test driven development with an extensive test suite to prevent bugs from ever happening again. All external contributions require a thorough code review to guarantee a certain level of quality.
Pro Terminal bell can be used to notify of completed actions
Terminal-bell gets passed through and marks the workspace visibly.
Pro VIM Style key bindings
You can configure i3 so that your keys for moving windows is similar to vim, for example, M-j to move the window down.
Pro Simple to use
Configuration is nearly automatic and simple, which can be really helpful to beginners.
Pro Awesome multi-monitor support
User can assign specific workspaces to specific displays as well as apps to workspaces. This makes possible opening set of most used apps with 1 shortcut always on the same screens.
Pro Never have to take hands off keyboard
Keyboard shortcut based navigation can seem daunting at first, but one quickly gets used to it. It enables the user to never have to take their hands off the keyboard, meaning that they can use their computer quickly and efficiently.
Pro Layouts can be saved and reused
Pro Great choice for keyboard users
The user keeps their hands in one spot (most of the time). One will find that the mouse is used less and less, making navigation quicker over time.
Pro Highly customisable
There are many customization options and possibilities to tweak the desktop, including widgets.
Pro Open source
Pro Looks beautiful
The design of the three built-in desktop themes; Air, Breeze, and Oxygen, are very beautiful to some.
Pro Has a file manager that provides a good balance between power and simplicity
Included file manager provides several icon, list and detail views to choose from along with features such as tabs, bookmarks, tagging, previews and metadata, network file access, bluetooth file transfers to/from devices and excellent removable storage integration while remaining fast and easy to use.
Pro Keyboard friendly
Nearly all actions can be driven with keyboard commands. Window management, including effects such as desktop overviews, can be triggered with a keyboard control (or mouse gesture) and some even support filtering results (such as windows shown) by typing. The KRunner tool (default keybinding: Alt+F2 or Alt+Space) provides searching local files, online sources, unit conversions, math and more all from a keyboard driven interface.
Pro KDE is an evolution on the classic desktop model
KDE 4 is a great evolution on the classic Win95/Gnome/XFCE approach. It's moving in innovative directions while respecting the classic metaphors.
Pro Active development
Pro Integrated advanced search
Plasma Desktop comes with an integration search system that makes it easy to find local files, emails, contacts, events and more. The file manager supports tagging and rating files as well as full-content searching and the KRunner command window and the Milou desktop widget makes searching for files, emails, applications and other content by name, subject, category, tag, fulltext, etc. very simple. It does this with essentially no noticeable interference with day-to-day usage of the computer, thanks to the scheduling built into the backend system (Baloo).
Pro Integrated components
Plasma Desktop generally comes packaged with a full set of applications to get users started, including a file manager (Dolphin), advanced file manager and browser (Konqueror), image and document viewers (Gwenview, Okular), the Calligra office suite, CD and DVD authoring (K3b) and dozens more. The desktop can be installed and used without these applications, but they add significant value for many people.
Pro Bunch of coherent applications
What make plasma so nice is the galaxy of apps, sharing same look and feel, configuration and behaviour.
Pro The search with the Windows Key is as awesome
Pro Adheres to standards
Standards adherence allows for interoperability and shared technology for X Window System desktops, with similar Wayland support being worked on. Applications not written with Plasma in mind work very well in Plasma as a result. The development team has also been instrumental in standard creation and adoption such as NETWM, X11 clipboard, icon themes, mimetype handling, application menu standardization, system tray protocols and notifications and more.
Pro The session manager works perfectly
This is a much better session manager compared to solutions from other Linux desktop environments.
Pro Multi-Device "Convergence"
Plasma Desktop provides seamless "zero config" integration of your Android device with your laptop and desktop machines via KDE Connect. Phone calls, SMS messages, cross-device copy and paste, media remote control, cursor control and more are supported.
The technology that Plasma Desktop is built on, simply called "Plasma", also provides interfaces for phones, tablets, netbooks, and media centers in addition to the desktop. These additional interfaces use the same underlying frameworks and therefore work well together and have a unified feel to them. They also support a common set of applications across them which adapt to the input methods and screen sizes.
Con Missing "include" possibility in config
While pretty good and easy to use for common tasks, the configuration language is missing the
include directive common in other languages. You can use a workaround - a shell script to config parts on demand. It would be best if this were built-in however.
Con No window gap option
You can do a lot with i3 but the official version lacks the option to have gaps between windows. However, there's a fork called i3-gaps that is almost the same as i3 except the fact that it lets you have gaps between windows.
Con Poor floating window support
Sometimes this is necessary, even when the Dev rejects feature requests. Firefox child windows (option dialog) is an example.
Con Steep learning curve
Has a steep learning curve for beginners.
Con It has some issues with transparency
Using transparent windows can cause them to crash.
Con Not very configurable
Unlike XMonad or Awesome, i3 can't be configured in a turing complete language, so it is much harder to alter its core functionality to do exactly what the user wants.
Con Documentation is online
Can't access it offline unless you download the page.
Con The plain-text configuration may not be suitable for beginners
i3 is configured through a plaintext configuration file. While it's very powerful and easy to learn, it may not be entirely user-friendly for those who have never edited a text configuration.
Con Manual tiling
The layout isn't automatic. The user must move panels manually and may indeed end up spending time on that rather than on working with the application.
Con No shortcut to switch between two recently used applications/windows
You can easily switch between two workspaces but not two windows (which are not adjacent to each other). The functionality simply isn't there and the dev refuses to include it as a part of i3 core. This can get annoying when you have multiple windows in the same workspace. There is a manual workaround though.
Con Perceived clunkyness and slowness
Compared to other options, KDE is still perceived slow. Especially, the desktop takes a few seconds to login.
Mouse pointer can feel sluggish, or laggy, on older systems
Con KDE is awesome but it is overcomplicated for newbies for sure
Way too many options for newbies to digest before the learning curve is over.
Con HiDPI support is spotty
The log in screen as well as some other components of the OS do not scale properly under HIDPI. Everything in the log in screen will be displayed too small, as well as some areas of the OS.
Con Interfaces are inconsistent and ugly in 4.x
While parts of KDE in 4.x can be very good looking, a common opinion is that the style is too hobbled together with inconsistent icons and styles clashing with each other.
Con Stability problems
Under certain conditions, most of KDE's components can be highly sensitive to race conditions, which leads to KDE applications frequently crashing, and, on rare occasion, kdeinit itself locking up.
Con Poorly named app menu with too many apps starting with "K"
This is better in KDE Neon with minimalist apps, which indeed in itself points out the problem.