My dad once said to me, "You give a lot of books three stars." I do.
This is definitely one of the best Narnia books, probably my third favorite. I love all the different places the characters sail to and the adventures they have. Eustace's main storyline stands out the most in my memory, but it's all so good.
You don't need the backstory of The Lion, the Witch and the Wardrobe or Prince Caspian but reading those two before this one enhances the story.