Sabai
I just use a Shunyata Hydra 4 with, EMM CDSA-SE, Martin Logan Monolith 3's, and BAT VK50-SE pre. The BAT VK60 amp has its own conditioner. I had demo'd both the QB8 and Shunyata Hydra and heard much more difference with the Hydra. This was also very expensive gear it was demo'd with, sometimes the results are easier to hear with very transparent gear.
As far as the Symphonies, I had the Pro and thought it did a very good job. When it was off, I would notice an immediate difference. Almost as if my ears were plugged a little and couldnt hear everything the same way. I guess everyone has different expectations and results. Sometimes I have found that you have to settle in with the unit for a while and then turn it off. This might be a better approach to finding the best place to put it. Find the best recorded music you can, it can help to pickup on things easier. Complex music might be difficult to initially judge from as you have to know what the unit is enhancing.