If you know one please tell me.

For the last couple of months I was trying various options for doing diffing and merging on Mac with git and perforce.

Perforce itself has pretty good merging tool p4merge and people already know how to setup it with git. It is good, but feels slow and does not allow to do dirs diffing (at least I don’t know how to do that).

The other option which I was using for a while is FileMerge (opendiff). Also good tool. You can find some articles about how to set it up with git, like Integrating Git with a Visual Merge Tool, this article also tells about other tools which you can use with git.

Strange that I did not see it anywhere in articles (maybe it is one of the new features in git) that you can use -d, --dir-diff with difftool. This is the description of this option

Copy the modified files to a temporary location and perform a directory diff on them. This mode never prompts before launching the diff tool.

For example by using it with opendiff

git difftool -d -t opendiff

You can get the list of all modified files in FileMerge window

After that just double click on files in the list to see the diff.

In conclusion I would just say - these two tools are good, but both require some time from you for gluing them with tools you use.

If you want easier way - buy Kaleidoscope. Yes, it is expensive for the diff/merge tool. But yes, it is worth it. Why? Because it requires only 3 minutes to set it up with almost anything, just check Kaleidoscope integration window