How/where are they over-rated? I'm not aware of any large amounts of praise being heaped on them, and as far as I know their new album isn't selling all that well. I stumbled across them on myspace myself. Their new album is the sort of metal I've been looking for for some time - super tech, brutally heavy and twisted as hell. And fucking WELL PRODUCED. So many Aussie bands fall flat in the production department.
Karnivool are a great band as well. While they aren't totally to my taste, they're undeniably good at what they do, and Themata sounds fucking amazing. I can understand all the praise and airplay they're receiving. I wouldn't call them a straight rock band either, they've definitely got metal elements in their sound as well as the whole progressive rock thing.