I’ve been using BC since the early 2000’s, so probably more than 15 years. I know it backwards and forwards. If you set it up right, it is pretty powerful. It allows a lot of the stuff that other tools fail on to be overcome. Manual alignment is a dream. The rules based comparison is very nice. Ignoring unimportant differences removes pretty much all the white space differences. The ease of selecting arbitrary blocks and moving them left or right is powerful. I’ve tried both Windiff and kdiff3 and both have missing features.

Back before git, it was common to take a massive set of changes and merge them manually when merging branches, and BC was the only tool that made it painless for me.

I stumped up my own cash for a pro license and I use it almost daily even now.