I finished this book yesterday and I absolutely loved it. I heard about this novel on the Book & Reader forum as a great fantasy novel - they were right.
This novel reminded me a lot of Ursula LeGuin's Earthsea series. The story is simple and delivered in a fairy-tale structure. It's a quick read but just beautifully written. Beagle unfolds his story with some fantastic imagery and metaphors. Not to mention some very fun characters. At the same time, he's kind of laughing at the traditional fantasy tale with his standard hero, villain, and maiden in need. But the story loses none of it's enchantment for these standard elements.
If you're looking for a fun and enchanting fantasy read, pick this one up. I've added it to my list of books to purchase and add to my collection because The Last Unicorn is one that I would like to read again.