Diffuse is a graphical tool for comparing and merging text files. It can retrieve files for comparison from Bazaar, CVS, Darcs, Git, Mercurial, Monotone, RCS, Subversion, and SVK repositories.
Good Diff N Merge tool, Just as someone Already stated I have yet to find a tool that can diff n merge 4, 5 or more files in just one shot. This is what I believe makes this app so unique. The comparison algorithm is decent enough, the only trade off is that Diffuse right now it's only a text base files comparison tool, does not compare binary files or directories, However keep in mind this tool still on Beta so even it lacks some major functionalities from other tools, Its "n" number of merge n diff, is way beyond the 3 way merge n diff. most tools offer.
Up to now I mainly used meld, but now I am using more and more diffuse because diffuse doesn't ignore differences in line ending style and it allows you to set manual alignments. The only feature I am currently missing in diffuse is a way to compare 2 or 3 directories.