They sound really good. I am hoping they don't actually sound too good, which is a strange thing to worry about, I suppose, but you want your mix to sound good on lesser speakers as well. Of course, I've got the Mixcubes for that.
I listened to a few other things that I had lying around the studio, including some AIFF files from Dream of a Far Light. The subwoofer was very excited to hear some of them. (I'm not sure if these were final files or test mixes that were sent down when I was recording a couple of Amy's fiddle tracks for the album. There was, however, a lot of bass down here. :) )