Not great. Old recordings almost always have hiss, and it's apparently not easy to get rid of it. I have some piano recs from the likes of Cortot and Lipatti, with hiss like a snakepit. One has to learn to listen past it, I guess. 
Sure. I don't care about the hiss. I have many many live recordings where hiss is abundantly there.
SO are coughing audience and shouting prompters. All adds to the excitement.
The new transfers seem to have louder hiss than the originals...
One could fear the upped loudness (see earlier posts) takes its toll on this aspect too. Unforgivable if true, if you ask me. The voice doesn't get any better though, and that should have been the sole priority imho.
cheers,
Marius
