It's a convolution reverb, but it only works with their library of impulse response samples, you can't load your own. Their library is really excellent and the plugin has a true stereo mode (some of the samples are true stereo). It's more a convolution rompler than a convolution reverb. Not that is a bad thing in this case.
Has a bizarre bug in Sonar where if you set it up on a track and then move the plugin (drag and drop) to another track/bus the settings change (not all of them but enough). Was driving me crazy till I figured out it was doing it. Doesn't do it in Abelton or Repear, only Sonar. That's still broken with this new release (in addition to the other problems).