I found this book kind of... ehhhh. It was a quick read, and Viguié had an imaginative twist for the story, but I got tired of Pearl's self-pity pretty quickly. The plot picked up with, not a love triangle, but a love pentagon, between Pearl, the prince, the mermaid... the mermaid's brother... and the translucently evil Sir Robert.
My favorite bit was Viguié's creative twist on mermaid-to-human magic. And it would be unfair of me to say she hasn't given the story a different angle. I certainly appreciate any version of the Little Mermaid that isn't Disney's. (Okay, it's possible that I appreciate that version, too, in some childish part of my heart.) However, this isn't one of my favorites, and unless you're a devoted fan of all variations of the story, you might pass this one up.