When comparing iTerm2 vs Mou, the Slant community recommends iTerm2 for most people. In the question“What are the best developer tools for Mac OSX?” iTerm2 is ranked 2nd while Mou is ranked 10th. The most important reason people chose iTerm2 is:
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.
Specs
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Pros
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 Extremely customizable
Other than being able to customize the various shortcuts, iTerm2 also lets you customize the colorscheme, font, transparency, etc.
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 Split panes
Easy to split panes to either horizontal or vertical sections. Makes it easy to observe multiple console windows.
Pro Completely free and open source
iTerm2 is completely free and open source. It's released under the GPLv2 license.
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 Cmd+D to split plane vertically
Very handy to use multi-tab.
Pro Can be configured as a drop-down terminal
Can be configured to work as a drop down terminal like Quake.
Pro Works well with tmux
The great mouse and clipboard support that are built-in go really well with tmux.
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 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 Cmd+Shift+I to Input all
Wanna SSH your server from multiple tabs, here you go.
Pro Advanced text editing
Mou has word auto-completion (accessed via 'esc') for English words, text transformation such as conversions to uppercase, blockquote or an h1 heading, HTML entities (such as <’s, &’s and spaces) that can be added anywhere in the text and customizable keyboard shortcuts for everything allowing for efficient use of the software's capabilities.
Pro Full syntax highlighting
Mou provides full syntax highlighting for Markdown. The highlighting can be customized manually or by applying a predefined theme.
Pro Has real-time split-screen preview
Mou is split into two columns. It displays raw Markdown on the left and formatted text on the right. Text on the right will update in near real-time as raw Markdown is written.
Pro Powerful search
Mou can do incremental ("find as you type") pattern matching search. For example, it can find all words that have x as the third letter followed by at least 4 more letters and a line break.
Pro Free beta versions
Mou is available as a free download up until the release of 1.0.
Pro Customizable
The whole editor can be customized using different color schemes and users can create own variations by editing CSS.
Pro Support for CJK characters
Mou supports CJK characters for writing Markdown in Chinese, Japanese or Korean.
Pro Export as HTML or PDF
Markdown can be exported as an HTML or a PDF file. Each export can also be styled by a custom CSS.
Pro Customizable keyboard shortcuts
Mou has keyboard shortcuts for all text manipulation actions allowing for highly efficient use of the software. These shortcuts can also be manually edited to better fit each individual workflow.
Pro Includes optional typewriter keypress sounds
The app includes optional atmospheric typewriter sounds that are triggered with each keypress. These can be enabled in the settings.
Pro Scriptogr.am & Tumblr integration via Dropbox
Mou allows writing and publishing to blogs from within the editor.
Cons
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 Doesn't support Snow Leopard 10.6.8
Some people still use SL.
Con Doesn't support RTL
Con No longer maintained
The latest version was released in 2014, version 1.0 was announced for 2015 but was never released. The app is not compatible with macOS Sierra.
Con Only free until 1.0 release
Once 1.0 is released (still unreleased as of May 2017, release was planned for August 2015), Mou will cost $30. It can currently be pre-ordered for half the price.
Con Text is hard to read on a big screen in full-screen mode
On big screens legibility is pretty bad when entering full-screen mode because the text is not columned nor centered. On smaller screens though, legibility is quite good even on full-screen.
Con Doesn't work as well with non-monospaced fonts
When using a non-monospaced font, the text jiggles around. It can be very annoying since users may not always want to write with a monospaced font.
Con Switching live preview on/off changes the width of text area
Con v1.0 was promised to Indiegogo founders more than a year ago
Safe to say this is dead software at this point.