I saw the Nostalgia Chick of it. The unicorn's singing was TERRIBLE too.
I think they picked the perfect people to do the voices of the main characters. I think they should've gotten Marnie Nixon or someone to do the singing, though, because Jeff Daniels and Mia Farrow can't sing. Not well enough to do their parts justice, anyway.
The story of The Last Unicorn is one of my favorites, too. And while I admit that the movie was not exactly the same as the book, I would submit that, compared with other movies based on source material (books, actual events, etc), they did a fantastic job of at least
attempting to remain faithful to the book, as opposed to, say,
Ella Enchanted,
The Black Cauldron, or
Legend of the Seeker. Kati chimed in with
The Lover, and
Exit to Eden as a couple more examples.
--Patrick