I'm very pleased with Amanda. It's not like it's a vocally challenging part of the song, and we all knew we weren't going to be getting Streisand. She did a nice job (that I'm sure looks great on screen) with a small portion of the song. I'm not a Kerry Butler fan, but the OBCR is the one time I really like her and I don't think it's really fair to compare them. Butler is a trained singer, and has been for most of her life. Amanda isn't. I must say that hearing her sing well was very satisfying.
Travolta, on the other hand, I'm not convinced will do well at all. Everything I've seen or heard from him just don't seem right. The part of Edna has always been where I was most concerned with this screen adaptation. I didn't know whether they were going for a more Divine feel where Edna never made jokes about the situation, never lowered her voice for a laugh, she was just a regular woman (who happened to be played by a man). Or if they were going to go with the Broadway approach, which was pretty much the opposite of all that: wisecracking, lowering Edna's voice at times for comedy, etc. Now it seems they're not going for either but a very off-putting, fierce, monster of an Edna. I don't know if I like it.
"Sing the words, Patti!!!!" Stephen Sondheim to Patti LuPone.