The qs-8s are some the best surrounds I have heard, they might be better than some average stand alone bookshelfs. I have them with the 80's and the 150 center. I dont believe you would find any distractions form the sound or looks from the b-stock from what I have read from others who have them. Some people cant even notice a difference. I dont know about the pioneer but can say read the forums and learn as much as you can. Different recievers with different watts per channel/ohms output will effect the sound stage of speakers and other issues including clipping,wall treatments,etc.. The 30-day trial is also a option. Keep reading and asking questions is a good way to go.
