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GNOME is an easy and elegant way to use your computer. It is designed to put you in control and bring freedom to everybody. GNOME is developed by the GNOME community, a diverse, international group of contributors that is supported by an independent, non-profit foundation.
SpecsUpdate
Pros
Pro Clean UI
Every aspect of GNOME has been crafted to fit together as a harmonious whole, so that it offers a consistent and integrated experience.
Pro Wayland support
Gnome is the first desktop environment that uses Wayland as default instead of X server. X server is only optional currently.
Pro Highly stable
Gnome isn't obviously devoid of flaws, but it's pretty stable - especially in comparison with the KDE Plasma Desktop, which can literally fall apart after installing upgrades (and show a considerable number of error messages) or for whatever reasons - after turning on the computer you can end up without (Plasma) desktop altogether, which is quite unproductive. It is also noteworthy that many other major desktop environments are based on Gnome, and among these are: Cinnamon, Pantheon and (now dead) Unity.
Pro Easy theming
Changing the look (and feel) of Gnome Shell is easy, shell theme, icon, windows and graphical elements (gtk) individually for each user.
Mostly it's installing some packages or unpacking some archive to a themes folder and using selecting the new theme in e.g. gnome-tweak-tool.
There are a lot of really good themes on DeviantArt.
Pro Gnome-Tweak-Tool is great
Gnome may seem bland out of the box but, the Gnome-Tweak-Tool is awesome.
The Gnome-Tweak-Tool allows for easy desktop tweaks and other control functionality, and that these features can be activated with just a click.
Pro Integrates with most Google Services
You can use your calendar, drive, contacts and most of Google services with Online Account option. You can show your Google Calendar events on the Gnome's default calendar app, Nautilus (Default file manager of GNOME) almost fully integrated with Google Drive and even you can read your PDF's with Evince (the default built-in PDF reader in GNOME).
Pro Effective default workflow
Gnome is not very tweakable but its defaults are sane enough that you it is very usable out of the box. Especially if you like a keyboard driven workflow and an uncluttered interface. The lack of options and features makes it a distraction free and clean UI to focus on what matters.
Pro All the major players in the Linux ecosystem have finally collated on Gnome
Red Hat default = Gnome
Fedora default = Gnome
Debian default = Gnome
Ubuntu default = Gnome
Opensuse default = Gnome
This doesn't mean the others go away, it just means there is a colossal community and industry backing behind Gnome.
The point whether or not it being technically the best option is now off table and irrelevant. It is now the de facto standard. Like it or not.
Pro Reall the only original and complete Desktop Environment
The Gnome-Shell paradigm is wildly different from Windows, and isn't all that much like OSX either - it's a different workflow that, if it appeals to you, is a dream to use. Every other DE is either like Windows, like OSX, or like OpenBox.
Cons
Con Longtime support is hard since every few years GNOME changes its own standards
Everytime something is complete GNOME breaks itself:
Icon naming changes almost every 3 years : once gtk icons were named stock_edit then gtk-edit then edit-edit and currently edit-edit-symbolic
- App icons change also every few years currently they get renamed to an android like scheme eg: org.gnome.Photos.svg instead of gnome-photos.svg however this breaks all common standards esp. since filenames on linux are case sensitive.
GNOMEShell extension also break on almost every release.
Currently Gtk3 has been stabilized however they are already working on GTK4 and 5 so in the worst case your desktop will need to run and support 4 GTK-toolkits at the same time.
Con Full screen start menu
This may be fine if your screen is really small, but on modern fullHD desktop it looks ugly and distracting. In addition to very ineffective display of items on screen - much more could be placed on one screen if there were less empty space around and between icons.
Con Continuous customization and extension issues
They need to sort out their continuous customization and extension issues, which are why many people still prefer KDE or other Desktop environments.
Con Some settings are not where the user would expect it
E.g. it is not possible to change the keyboard auto-repeat delay or rate from the usual All Setting > Keyboard like, for example, in Unity.
Many settings are considered "tweaks" and require installing a separate utility to adjust.
Further still, some settings are buried in a dconf database.
Con Default alt-tab behaviour is cute but extremely annoying for fast keyboard users
Con Native Gnome dock isn't scalable
The native Gnome dock isn't scalable, which means if you want to change its size you have to download a customized theme for the shell and hope it has the appearance you want. Honestly again just like the icon issue it wastes way too much of the screen on high resolution monitors.
Con Tightly coupled to its window manager
If you're looking to run an alternative window manager, like XMonad, you're pretty much out of luck.
Con Extension system is weakly integrated into the environment
Backward compatibility is not guaranteed and extensions seems like second class citizens in the GNOME environment.
Con Depends on systemd
Some people don't like systemd but it is part of most modern distros anyway.
Con Icon scalability and sorting
The icons in the "apps view" area don't have any additional sizes, the current ones are much too large to be effective for the screen space they use. Also, there is no native way to sort them in Gnome, only a very limited extension. Which means you're pretty much always better off using the search bar if you can.
Con Shell-Style ≠ Widget-Style
The GNOME-shell is unable to use the current GTK style for its interface thus making it hard to get a consistent user interface.
Con Inconsistent desktop
As of GNOME3, some applications have ClientSideDecorations while other use normal Titlebars, this also affects usablity since both Decorations do different things if you left, right, or double click it. Same goes for Menubars. Some Apps follow the GlobalMenu in the GNOMEShell while others don't.
Con Non-intuitive use paradigm
It doesn't feature an always-on dock and fixed amount of usable desktops, doesn't support tray icons for background programs. The main interaction with running programs bases on clicking and dragging (to a desktop) preview thumbnails.
Recommendations
Comments
Flagged Pros + Cons
Con Limited customization
To modify anything beyond the wallpaper requires third-party software.
Con Hefty (lots of dependencies)
Gnome 3 in the current state is heavily weighed down by having a lot of functions as requirements, rather than options. You MUST have their email client, calendar, and more installed as the environment relies on them directly for basic functionality. Which is absurd as most other DEs don't require a specific calendar program just to tell you what day it is.
Con Gnome search indexer (tracker) consumes your CPU even on battery
If you have large home directory with lots of file, Gnome search indexer Tracker tries to index all the files and it takes forever to complete. During indexing, it uses all you CPU and if you are on battery it will drain you battery instantly.
Con Looks more like a phone interface than a desktop
Con Gnome
Arrogant and incompetent developers, not easy to customize and what can be customized is thru flaky extensions. Should be orphaned and left for dead
Con Geared towards touch input
Oversized buttons and menus reduce keyboard and mouse efficiency.
Out of Date Pros + Cons
Pro Fallback mode offers a classic look
For people looking for older, more classic looks, Fallback mode offers just that. Ubuntu users can have this option by installing a package called "GNOME-Session-Fallback." In the future to be released GNOME 3.8, the Fallback Mode will not be included, so this is really not a long-term solution.
Con Some areas are unpolished and lack features
Some aspects are still unpolished and lack features - the gnome design team works well, but seems to not be taking input from the outside world.
Con High memory usage and bad performance
Gnome Shell takes huge amount of RAM. It can be horribly slow on some machines (depends on combination of graphics hardware and drivers).
Con Themes tend to break on every new release
On every new release of Gnome Shell a lot of themes tend to be broken. After happening so many times a lot of themers gave up working on Gnome. This is why compared to Gnome 2 there are few themes that actually work on the latest release.