I've heard that Perforce is very good at merging, I'm guessing this has to do with that it tracks changes in the form of changelists where you can add differences across several files in a single blow. I think this implies Perforce gathers more metadata and therefore has more information to do smarter merging (at least smarter than Subversion, being Perforce centralized).

Since this is similar to how Mercurial and Git handle changes (I know DVCSs track content rather than files), I was wondering if somebody knew what were the subtle differences that makes Perforce better or worse than a DVCS like Mercurial or Git.