When comparing IntelliJ IDEA vs CodeCompare, the Slant community recommends CodeCompare for most people. In the question“What are the best diff tools for Git?” CodeCompare is ranked 9th while IntelliJ IDEA is ranked 11th. The most important reason people chose CodeCompare is:
It does not add a blank line in the other code-pane to show where code was added or deleted. It simply draws a line to show point out its location.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Smart refactorings
IDEA places an emphasis in safe refactoring, offering a variety of features to make this possible for a variety of languages.
These features include safe delete, type migration and replacing method code duplicates.
Pro Fast and smart contextual assistance
Uses a fast indexing technique to provide contextual hints (auto-completion, available object members, import suggestions).
On-the-fly code analysis to detect errors and propose refactorization.
Pro Android support, JavaEE support, etc
A very complete development environment support.
Pro Support for many languages
IntelliJ supports many languages besides Java, some of these are: golang, Scala, Clojure, Groovy, Bash, etc.
Pro Lots of plugins
Many plugins are available for almost any task a developer may need to cover. Plugins are developed by Jetbrains themselves or by 3rd parties through the SDK available for writing them.
Pro Stable and robust
IntelliJ IDEA hardly ever crashes or has any issues that plague other Java IDEs like file corruption or slowness.
Pro Intuitive and slick UI
IDEA has a clean, intuitive interface with some customization available (such as the Darcula theme).
Pro Clear and detailed documentation
The documentation is exhaustive, easy to navigate, and clearly worded.
Pro Very powerful debugger
With ability to step into a certain part of a large method invocation (Shift+F7), drop frame, executing code snippets, showing method return values, etc.
Pro Free version available
There is a free community edition (open source) and an ultimate edition, which you can compare here.
The ultimate edition is available for free for one year for students but must be registered through an .edu e-mail account.
Pro Many convenient features
These simplify the daily work, e.g. copy/cut a whole line without the need to select it.
Pro Gradle support
Pro Built-in Git support
Pro Student Benefits
Verify yourselves as a student to get more perks.
Pro Embedded database support
Creating an embedded database, running SQL script in a dedicated terminal, viewing tables and their contents, and creating a connection to an in-memory or embedded database is fully supported.
Pro Prices are not bad
I pay $24 a month and i have access to all jetbrain peoducts , so i use their many tools , i tried many others like netbeans , eclipse , etc , they re good but intelij is on the space and the sky is the limit . Been using it for 5 years and i cant tell i got frustrated using .it
Pro Graphical showing of where code is added or removed
It does not add a blank line in the other code-pane to show where code was added or deleted. It simply draws a line to show point out its location.
Pro Three-way comparison and automatic merging
Three comparison panes with horizontal and vertical layouts
- Integrates with version control systems as the merging tool for conflicting file revisions
- Non-conflicting changes are merged automatically
- Merging conflicts are highlighted
- One-click conflict resolution with a mouse button
Pro Supports comparing folders
Can diff entire folders.
Pro Integrated into Visual Studio
Can be used either as a stand-alone product or as the built in diff/merge tool for Visual Studio.
Pro Clear overview that marks only the changes, not every line with a change
Most compare tools mark every changed line with colour, making the code just a mess with thousands of coloured lines, while all that might be changed is a sign/character on each line. Code Compare draws boxes around each changed segment and highlights only the real change with a colour.
Pro Offers free version and paid for version
You get a lot more if you pay for the pro version.
Cons
Con Slow startup
Startup can be slow depending on system configuration.
Con Uses a lot of RAM
Con Somewhat expensive
IntelliJ IDEA is fairly expensive, with a pricetag of $149/year.
However there is a free community edition available.
Con Built with closed source components
The version with full features is not opensource. Parts of the code are under apache licence though.
Con Cannot open multiple projects in the same window
Con Lack of plugins
IntelliJ supports a very small amount of plugins. Although these are 'quality approved', many features are missing and can't be implemented because of that.
Con Bugs are not solved as often as they should
They are more interested in adding new features or issuing new versions than solving bugs.
Con Standard hotkeys behave differently
Seems like hotkeys assignment in Idea has no logical consistency.
Like «F3» is usually next match, «Ctrl+W» - close tab, etc — they map to some different action by default.
There is a good effort in making the IDE friendly for immigrants from other products: there are options to use hotkeys from Eclipse, and even emacs. But these mappings are very incomplete. And help pages do not take this remapping into account, rather mentioning the standard hotkeys.
So, people coming from other IDEs/editors are doomed to using mouse and context menus (which are rather big and complex).
Con No longer supported
Problematic with Visual Studio 2022. Semantic code comparison (its main selling point) does not support newer language variations.
Con Does not support custom comment markings
Some compilers use ";" to specify in-line commenting. But as that is not a common method, all added comments are marked as new code. So it becomes difficult to find changes in the functionality of the code.
Con Does not support move-detection
Very few programs detect move of blocks of code. Most just show deleted and added instead.
Con Free version is limited
Whereas there is a free version, it is missing a lot of great features that you're forced to pay for if you want.
