I'm probably one of the few that thinks that the single band units are better, the QSD-1 which I have colours the sound quite a bit. The QS-D1000 is an audiophile unit through and through. I was very tempted to buy it, I see that it sold quickly. In hindsight I suppose that I could of bought it and then sold the QSD-1. I already have a Photolume unit which is a QSD-2 clone, it just lacks the All-pass phase shift network designed to keep the front and rear QS decoded signals in phase with each other. That network is undesirable for stereo enhancement anyway; I say enhancement as really nothing is synthesized by this process, the stereo stage is just stretched around the room. I recently purchased an Involve decoder evaluation board, i haven't tried it out yet, it's a triple band unit but by using DSP it might colour the sound less than the QSD-1. What's really better an analog unit with minimal signal processing or a DSP unit with more advanced processing. I hope to be able to report on my findings soon.