Book Burner has definitely grown on me from when I first listened to it, but I'm not sure where it'll shake out in terms of comparisons to other PD albums as well as the other great albums of 2012 in general. It'll probably be in my top twenty or so, but I'm not sure about top ten. Maybe. We'll see.
UFOmammut, however...that shit is top ten for sure. No doubt about it. Holy fucking sweet Satan is that album a monster.
EDIT: I hadn't thought about reviewing Opus Primum and Opus Alter together like you did. Not sure if I'll do that or review them separately. I guess it makes more sense to put them together as one album, though.