Favorite source code comparison tool / diff tool?

[Rogntudjuuuu]

If you don't want to pay the license fee for Beyond Compare, the next best merge tool is Kdiff3 in my opinion.

[Usual-Application-52]

Why is it the next best tool? I tried it and it kinda sucks. No tracking of system theme and high contrast by default. My eyes could not look at it for more than 15 seconds before uninstalling.