Eh, I am coming from the perspective of a user, not a VCS developer. I find git repositories way easier to navigate, let alone perform complex operations on, because how they work couldn't make more sense to me.
Being an active user of both git and hg, I also can't think of any features I make extensive use of in git (rebase, feature branches, etc) that I can't get with hg. My workflows in both are pretty much the same, just a saner interface on the hg side. If anything, git doesn't have revsets, a really powerful query language you can use to sift through your history - see http://www.selenic.com/hg/help/revsets