When comparing GitExtensions vs TortoiseGit, the Slant community recommends GitExtensions for most people. In the question“What are the best Git clients for Windows?” GitExtensions is ranked 7th while TortoiseGit is ranked 9th. The most important reason people chose GitExtensions is:
It's totally free And its written and thought by developers who really know what you need as a developer. Open to contributions by everybody.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Open source
It's totally free
And its written and thought by developers who really know what you need as a developer. Open to contributions by everybody.
Pro Git commands visibility
GitExtensions typically displays all commands that it carries out in a separate window. The user can also open the Gitcommand log (under Tools) and view the git commands as they interact with the program.
Pro SSH support
Instead of using HTTPS and authenticating every time they are pushing their code remotely, plenty of developers prefer to use SSH to communicate with the remote server and authenticate using secure key pairs.
Pro Powerful commit screen
Staging/unstaging files and/or lines of code, ammending, overriding commit's author, commit templates.
Pro Many advanced features made easier to use
Complex git commands such as resolving a rebase conflict or performing a subtree merge are made much easier by a helpful UI.

Pro Great UI
GitExtensions has a simple layout, all usual functions being available without navigation menus. The branching and merging are clear and easy to follow.

Pro Lightweight and fast
GitExtensions is a lightweight and fast application.
Pro Very good stash support
Easy to save, view & pop stashes.

Pro Easy to set up
Can either be set up as a shell extension, standalone tool of Visual Studio plugin, allowing developers to choose the way that suits their workflow best and is easier for them to get into.

Pro Easy to use
Can be used as a Visual Studio plugin for developers who use it as their IDE, or as a standalone tool. Both are easy to use even for users not very familiar with git.
Pro Submodule support
Powerful submodule support, also when working with multiple cloned SuperRepos.
Pro Responsiveness
Pro Useful plugins
Includes Gitflow, also has a delete obsolete branches feature which is very useful to get rid of those old branches that have already been merged. There are also other options to clean overall clutter in repositories.
Pro Built-in git-bash console
This makes running custom git commands quicker.
Pro Eases initial git configuration
The settings window on first run helps you set lots of required settings such as your commit email address.
Pro Simple global / local diff and merge support
Makes working with repos using different languages and support tools much easier.
Pro Allows easy setting up of scripts to enhance productivity
Pro Plugin API
There are several out-of-the-box plugins installed with standard setup. Additional behavior customization is possible with new plugins (written in C#).
Pro Integration with common tools like Jira or TeamCity
Pro Open source
Licensed under GPL.
Pro Windows context menu integration
Context menu enables access to common commands quickly.
Pro Can parse and provide a pretty log of all commits or filter by branch
Pro Convinient blaming tool
Very friendly blame tool. Easy to walk in the history of a file.
Cons
Con No side-by-side diff
There is no option to do side-by-side review of files. Creator(s) do not feel this is a desirable feature. While this is great software in almost all aspects, not giving the end-user a choice of side-by-side diff (inside GitExtensions) is a deal-breaker.
And no, using an external tool to do this is too much of a hassle, because of the amount of files to check in each change-set (in my case that are often 200 to 300 files).
Con Not truly cross-platform
GitExtensions is not truly cross-platform. It can run through mono on UNIX-based systems but this does not work as well as it does on Windows.
Con Missing tabs to have more repositories open at once
Con Doesn't offer " Repo Groups"
Repo groups (best done in smart git, Git Kraken's version is also decent) is an amazing time saving feature when you work with multiple repos on a daily basis. This is the only con!
Con UI does not render properly on Windows 10 x64
Con UI may feel cluttered with too much information
The sheer amount of information that the UI displays by default may feel overwhelming at times, if not outright confusing.
Con Linux version has no updates
If you want an updated version, you have to download the source and figure out how to build it yourself. Developers don't have any kind of documentation or faq about this process.
Con Windows only
No Linux or OSX versions available.
Con Renames git commands
Makes things hard to find for people used to the git CLI.
Con Buggy file status icons
The file icons are also often buggy and do not reflect its true status. Often times the icon is missing and makes you think a file or folder is untracked, when it is already staged, or sometimes even already committed and pushed.
Con May clutter your Windows Explorer
If you have synced your dev folder to a cloud service, TortoiseGit's git status file icons will override your cloud provider's icons.
Con No support for staging
It does not support staging in any way. You'll never guess that this feature is exist in git.
