You can never have too many Joni Mitchell threads.
Yes, I'm excited about it and her voice sounds stronger than her last album, based on these clips. I actually prefer her more recent, lower singing voice; her first three albums are especially unlistenable to me because she's singing so high. Her phrasing has also greatly improved over the years.
Unless I'm mistaken, Herbie Hancock did not play on Court and Spark, but I believe he does play on this one; incidentally, he is releasing a new album the same day that "Shine" comes out, entitled "River: The Joni Letters." It's mostly instrumental versions of Joni's songs, but there are a few guest vocalists - including Tina Turner on "Edith and the Kingpin," which I found a bit odd but I did hear a clip and it sounds damn good.