I use it as a curtain, I have it ruffled so it would serve better as a diffusing surface as well (I'm not an expert on these sort of things, it just seemed like a good idea). I didn't expect it to block the sound because there is an air gap between the curtain and the wall and the curtain is not so thick anyway, but I think it does help with the acoustics of the room a bit.
A customer said it has a weird smell in one of the former reviews, I must say I didn't get the same impression. If you stick your nose in it you will certainly feel it, but I cannot say that it changed the smell in the room to the degree that it would make me particularly notice it and if I did I would just wash it.
Quality of it seems good, it doesn't release fabric particles.