Just finished watching the restored blu-ray of "Suspiria" with the "original 4.0 English sound mix". I had never seen this movie before, and I have to say I really enjoyed it... a bit of a "b-movie" feel, but plenty of suspense, gory practical effects, and gorgeous cinematography. The visual images are extremely clear, perfectly restored, and vibrantly colored... this movie has a "primary color" palette and every scene and frame feels purposeful. The images look like they could have been filmed yesterday. As far as the surround mix goes, I tried every audio stream available on my OPPO, and none of them were 4.0. However, the one labeled as "English 4.0" had excellent sound quality (the best of the available streams) and tasteful use of the surrounds... but there was definitely sound coming from the center channel and my subwoofer. This is a winner for fans of vintage horror and stylistic cinema. My only disappointment: a horror movie set in a dance school filled with beautiful 20-somethings and I don't get to see one of them naked?!
Edit: Is it possible my OPPO was outputting a 4.0 stream, but my amp was doing something to turn it into a 5.1? This doesn't happen when I listen to quad audio discs, so I'm not sure why it would happen with a 4.0 DTS-MA disc, but who knows...