You are going to get a variety of differing opinions on this one. I would think it depends on how close the the rear surround you will be. If it is right behind you I would recommend a qs8 to diffuse the sound a little. If you sit a ways away from it I would think a direct firing speaker such as the m3 would be the best as it is far enough away to allow dispersion but still maintain a slight localization which is what I think the dolby labs had in mind when they added the rear channel. JMO