DiffMerge is an application to visually compare and merge files on Windows, OS X and Linux.
Ranked in these QuestionsQuestion Ranking
Pro Completely free
Pro Cross platform
DiffMerge is cross platform and is available for all major operating systems. This means WIndows, Linux and OSX
Pro Three way merges
DiffMerge supports three way merges.
Pro Folder compare
Con Startup time can be slow
DiffMerge's startup time can be quite slow sometimes.