I have used it (the demo version) for facial reference before, and I think Alan has played with it too.
I toyed with buying the full version a few years ago, when I was doing comic work, so I could save character heads and be able to position them, even change their expressions. But it's marketed to 3d game designers and is therefore too expensive for a hobbyist. But it's so fun to play with...the demo can be a real time waster.