Head over to the MakeHuman website, in case you would like to test out the new macro-expressions they are developing and testing right now for the next MakeHuman release. In addition they also updated their exporter so it can generate a MHX Rigify checked character which works seamlessly together with Nathan Vegdahl's Rigify Add-On. Deformation has been improved by adding extra deformation bones. It is definitely not perfect, but the most awkward defects are gone.
The interface offers now sliders for facial expression generations. Based on what part of the face you work on, the expression options you can adjust will change accordingly. The areas you can work on are quite many. Besides the usual eye, mouth, nose, options you can also work the throat muscles as an example.