[bmitc]

I setup Git to use Perforce’s P4Merge as the Git mergetool. P4Merge is cross-platform and free and quite good.

[diego_moita]

There are 2 things to consider when comparing them: 2 panel diffs and 3 panel merging.

P4Merge is very good at the second but not so much at the first.

Also, to this date it doesn't have an OS-X version for M1 CPUs.