When comparing difftastic vs Kaleidoscope, the Slant community recommends Kaleidoscope for most people. In the question“What are the best diff tools for Git?” Kaleidoscope is ranked 4th while difftastic is ranked 18th. The most important reason people chose Kaleidoscope is:
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.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Can diff directories
Pro Syntactic diffing
Down to a character.
Pro Cross platform
Linux, Mac and Windows.
Pro Supports over 20 languages (and some other syntax)
c, c++, c#, java, python, go, javascript, json, rust, sql, html, css and more.
See here.
Pro Language autodetection
Pro Has a manual
Pro Supports other version control tools
Like Mercurial.
Pro Works with Magit
Pro MIT license
Pro Has syntax highlighting
That can be turned off.
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.
Cons
Con Can be confused with syntax at times
Con Mac OS only
Kaleidoscope is a Mac OS X only app.
Con Paid software
Kaleidoscope is not free, costing $69.99.