When comparing Kaleidoscope vs CodeCompare, the Slant community recommends CodeCompare for most people. In the question“What are the best folder/file compare/diff tools for either OSX, Linux or Windows?” CodeCompare is ranked 10th while Kaleidoscope is ranked 12th. 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
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Pros

Pro Simple UI
Kaleidoscope has a beautiful and simple UI. It displays the two files that are being compared side to side, highlighting all the differences in a way that's easy to understand.
Pro Diff within a line
When working in code, line-by-line diff can still be hard to spot small changes within the line. Kaleidoscope will highlight what has changed.
Pro Supports comparing folders

Pro Image difference viewer
Kaleidoscope supports image diff viewer in addition to git diff. It's able to find even the slightest changes between two versions of the same image.
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 Mac OS only
Kaleidoscope is a Mac OS X only app.
Con Paid software
Kaleidoscope is not free, costing $69.99.
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.
