Gala is a window manager / compositing manager and an integral part of Pantheon, the desktop environment of elementary OS.
Ranked in these QuestionsQuestion Ranking
Pro Beautiful, uniformly designed, and sleek
Gala is designed to be unimposing while still remaining functional and pleasant to look at. By following the elementary OS design guidelines, Gala maintains a very consistent look.
Pro Easy for Linux beginners who are coming from legacy OSs
Gala has limited configurability which keeps things simple.
Pro Extremely fast
Gala works well on limited-resource hardware, e.g older netbooks and Chromebooks.
Pro Works with Gtk client-side decorations
The current bets of elementary OS (Freya) has enabled the use of Gtk client-side decorations.
Pro Hotcorners give shortcuts for multitasking, window management, or custom commands
User-configurable hotcorners means power users get four super easy shortcuts for multitasking, window management, or custom commands.
Pro Excellent stability
Despite the current stable release only being on version 0.2, it is very stable.
Pro Integrated compositing manager allows for fancy effects and animations
The Gala compositing manager allows for effects and animations to be used on a window by window basis.
Pro Dynamic workspace management
Workspaces are added and removed on the fly so you only have as many as you need at any given time.
Pro Innovative multitasking
Gala takes some hints from mobile OSes, but handles multitasking in a powerful way designed for desktop. Workspaces and alt-tabbing work well and are familiar, but feel smoother than alternatives.
Con Limited configurability
Configuration options are few and far between and require editing settings with dconf editor.
Con Buggy with nVidia Graphics
It's fantastic with the Intel integrated graphics; however, it is not good on nVidia ones
Con Not very lightweight
Although it certainly does not eat up CPU or RAM, it is not as lightweight on resource usage as awesome, i3, openbox, for instance. This shouldn't really be a surprise however.
Con Hard to install on some distros
While Elementary OS has Gala built-in, it might be difficult to set it up on certain distributions because it's tailored to Elementary OS only. Arch, for example, only supports Gala via AUR at the moment.
Con Does not render well under AMD graphics
The underlying compositor is know to have issues with AMD graphics cards, leading to poor performance, stuttering, and graphical artifacts.