I use kdiff3 or bc4. I find those tools more powerful for fixing complicated merges and just as easy for simple ones (eg manual alignment for when the merge algorithm can’t recognize what is supposed to be aligned)

I’ve tripped over the exact scenario you mention in that post more than once. Usually, it’s not that I end up including an entire function that shouldn’t be there, though. I find it tends to be more like “Oh, here’s an extraneous bit of code that just showed up in the middle of this method. Hmmm....” Or, alternatively, I end up removing too much code, rather than too little.