I mean you can't really compare them since git doesn't even _have_ branches as Mercurial understands them. git's branches would perhaps better be called twigs in comparison. git's lightweight branches better map to Mercurial's topics or bookmarks, though neither perfectly. And Mercurial has even lighter weight branches since you can just make a new head by committing without having to name anything, and it won't yell at you about a detached head like git will.