When comparing Kaleidoscope vs DeltaWalker, the Slant community recommends Kaleidoscope for most people. In the question“What are the best folder/file compare/diff tools for either OSX, Linux or Windows?” Kaleidoscope is ranked 12th while DeltaWalker is ranked 17th. 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
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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 Folder and file filtering
Easy to use rules for including or excluding folders and files from your folder comparisons.
Pro Cross platform
Works on Mac, Windows and Linux.
Pro Image comparison
2 & 3-way image comparisons with zooming & panning are available.
Pro 3-Way Text Merge
Pro Can compare remote directories
Can connect to remote folders via FTP, SFTP, FTPS, WebDAV, WebDAVS, Dropbox, and Google Drive.
Cons

Con Mac OS only
Kaleidoscope is a Mac OS X only app.
Con Paid software
Kaleidoscope is not free, costing $69.99.
Con Very slow
Folder comparisons can take an extremely long time to load compared to other diff tools.
Con Can't save sessions
