Just got back from a 35mm screening. Some thoughts...
The movie was deafening. I had always heard it was supposed to be loud, but hearing it in your living room (especially if you own the U.S. DVDs) does nothing to prepare you for just how loud it is in theaters. Forget action movies with tons of helicopters and explosions--this was the loudest movie I have ever sat through. The rainy cab ride in the beginning was so loud, it was hurting my ears. I can completely understand the effect the music was supposed to have on the audience in 1977 now, as it overwhelms you in the theater. The sound mix on the European releases is closer to how it sounds in theaters, but forget the U.S. DVDs, as they use the Anchor Bay remix and seriously tone down the volume. You have not heard Suspiria if that is all you have to reference.
Speaking of the soundtrack, the U.S. DVDs also have many more edits, such as a creepy howling starting up just before Pat's murder which is not present on the U.S. DVDs but is present on the European releases. One hopes when Synapse eventually releases their Blu-ray that it has the correct soundtrack, meaning it needs to be LOUD and have all of the original sound effects.
One thing Anchor Bay did get right was the colors (Blue Underground did, too, by default, as they used the same master for their release). The U.S. DVDs are the closest to the theatrical presentation as far as colors go. Don't even get me started on the European Blu-rays from various countries. I have seen several and own one, and the colors are so far off, one has to wonder who was ultimately responsible for how those turned out and how they got so far off base.
Speaking of the colors, they aren't as wild as the film's reputation leads one to believe. Many scenes have quite normal lighting and the primary colors only really have a big effect in certain scenes, such as Sarah's chase/death scene. The film is beautiful, obviously, but Dario's thematic sequel Inferno wins the nod as the more wild of the two, color-wise. In terms of crazy lighting, that film (especially on the cinematographer-approved German release) blows Suspiria out of the water.
The cut I saw was the U.S. release print, so the murders were edited for violence and the scene where Ms. Tanner confronts the pianist about the dog attacking Albert is missing, which honestly made the film more effective in a way as it led one to believe the witches were killing just for the sake of it because they're evil. When Sarah tells Suzy about the weird happenings that Pat had been writing down and when Olga and her friends mention there might be a hex on the place, it rings even more sinister in light of Daniel's seemingly senseless death in this cut. It's the only edit I actually agree with, as obviously the truncated violence was not a plus.
If you ever get the chance to see this in theaters, do it!