When comparing Alacritty vs iTerm2, the Slant community recommends iTerm2 for most people. In the question“What are the best terminal emulators for Mac?” iTerm2 is ranked 1st while Alacritty is ranked 5th. The most important reason people chose iTerm2 is:
Other than being able to customize the various shortcuts, iTerm2 also lets you customize the colorscheme, font, transparency, etc.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Blazing fast rendering with GPU-accelerated
Written in Rust with a philosophy focusing on speed and simplicity, Alacritty is one of the fastest terminal emulators out there.
Pro Looks good
Alacritty looks very slick on Linux, especially with GNOME or i3.
Pro Simple configuration
The configuration file is very well made and easy to use. You can fine tune your preferences to perfection in a matter of minutes.
Pro Comprehensive font options
Alacritty can be configured to adjust line spacing (height), letter spacing (width), and individual character horizontal/vertical positions.
Pro Has support for image previews in w3m and ranger
Pro Has text ref-low when window is resized
Pro Fast and simple but with true color support
It's simple and fast like xterm or urxvt but with truecolor support which is a big plus if you use a terminal based code editor. Basically Alacritty has all the features you need and nothing you don't (if you're using tmux for multiplexing).
Pro Extremely customizable
Other than being able to customize the various shortcuts, iTerm2 also lets you customize the colorscheme, font, transparency, etc.
Pro Autocomplete is built-in
iTerm has autocomplete features built in. It remembers your past commands and when you are writing something on the terminal, simply pressing Control-;
it will show you a drop down menu of suggestions from which to choose.
Pro Complete out of the box
Unlike most terminal emulators, iTerm2 comes with a pretty complete set of features. It has built-in search, autocompletion, tabbed navigation, Growl support and even a built-in clipboard manager for various API keys and such.
Pro Fine tuning for fonts
It's possible to choose a font and adjust vertical and horizontal spacing.
Pro Can immediately open files inside a text editor
You can Ctrl+Click on a file path to open said file in a text editor.
Pro Supports mouse actions
Has support for mouse actions like clicking, dragging, selecting, etc.
Pro Active maintainers
Issues resolved fast by quality contributors.
Pro Works well with powerline fonts
Pro Completely free and open source
iTerm2 is completely free and open source. It's released under the GPLv2 license.
Pro Split panes
Easy to split panes to either horizontal or vertical sections. Makes it easy to observe multiple console windows.
Pro Supported by many applications as a terminal app selection
If an application has terminal integration, there is high probability it allows iTerm2 to be selected.
Pro Cmd+Shift+I to Input all
Wanna SSH your server from multiple tabs, here you go.
Pro Intuitive
Pro You only need to type in commands once
iTerm2 can store up to 4M of history of commands you already used. This, coupled with the built-in search features makes it possible to type a command only once and then search for it through the history for subsequent uses.
Pro Works perfect with Oh My Zsh
It's a perfect base to add Oh My Zsh on top of it and enjoy a lot of themes and a really pleasant look and feel.
Pro Works well with tmux
The great mouse and clipboard support that are built-in go really well with tmux.
Pro Any key can be mapped to any function
Using the Preferences Menu you can set up hotkeys to map virtually any action you can think of to a single key or a combination of them. This is extremely helpful as it allows you to use shortcuts to edit commands you are typing in the terminal and while most terminal emulators have shortcuts for this sort of thing, few of them let you define your own.
Pro GPU-rendered, blazing fast and super smooth
Many people say they use Kitty or Alacritty because they are GPU-rendered. That was true a long time ago. But iTerm2 has been GPU rendered for years now. It's so fast and smooth that you soon forget you are in a terminal.
Pro Beautiful, minimalistic and elegant UI
It's super-clean and during use it gets completely out of the way, it's a beautiful canvas for your terminal work, a pure joy that never gets old.
Pro Can be configured as a drop-down terminal
Can be configured to work as a drop down terminal like Quake.
Pro Cmd+D to split plane vertically
Very handy to use multi-tab.
Cons
Con Cannot into ligatures
Alacritty does not support ligatures in Fira Code, Iosevka etc.
Con Unreliable Font Rendering
Like a box of chocolate you never know what you're going to get.
Con Sacrifices basic features for raw performance
The Suzuki GSXR of terminals. Or your ditzy, blonde high school cheerleader; fast and pretty but not a lot going on under the hood.
Eschews a negative developmental philosophy towards including said functionality, with the official reason cited in project documentation as "Not within the realm of a terminal emulator" and ostensibly, "best left up to other tools such as terminal multiplexers" [such as screen or tmux]. Which is unfortunate when you factor in speed against terminal with the functionality built in vs their reliance on 3rd party tools:
tmux on alacritty: 'find /usr' time: 3.234s, cpu: 72%
tmux on konsole: find /usr' time: 1.777s, cpu: 96%
See issue here.
Con Keycodes are not passed through following Linux standards
If you come from a Linux terminal emulator (Gnome Terminal, Konsole...) and you rely on key-combos that are widely supported in those, porting the same functionality to iTerm is possible but will require a lot of research and configuration on your part, so account for a long painful adoption period.
Con Not quite as fast as Alacritty or Kitty
Comparing these 3 terminals on the same machine/config, iTerm stands out as the slowest of the bunch. The difference may not be noticeable to all users.
Con Way too many menu items and settings
Finding the right one is like searching for a needle in a haystack.
Con Doesn't support Snow Leopard 10.6.8
Some people still use Snow Leopard or other 32-bit systems.