I really liked this book. It might even be my favorite Shannon Hale book, and to think I almost didn't read it. Like I reviewed previously, I wasn't a huge fan of Enna Burning. I thought it was quite dark compared to Hale's other works. River brings everything back to where it should be - a fun, light-hearted, page turner.
I loved Razo's character development in this book. He struggled with realistic self-doubt throughout, but gained confidence as time went on. It helped that his friends and leader were also subtly (and sometimes not so subtly) encouraging him along the way. The scene near the end where he realized he has grown was priceless. I also really liked how difficult it was for Enna to recover from the war. It made sense that she would feel guilty and doubt her abilities. The scene near the end where she is able to control her power was wonderful. I was so excited and happy for her. I also found Dasha a delightful and clever character, and thought his Radiance was fabulous. I would love to know someone like him in real life.
The mystery of who was setting up the Bayern was fun. I did figure it out (barely) before Razo (me being an armchair sleuth and all), but it had me guessing for most of the book. The other side stories were also enjoyable. **SPOILER ** My favorite being Finn's learning of a harp to propose to Enna. I actually had a roommate proposed to in the same manner. The fellow's voice was probably just as bad or worse than Finn's. My other roommate and I almost died trying not to laugh, while the girl being proposed to cried throughout. Oh true love. **END SPOILER**
Overall, highly recommended! Oh, and I suggest you read all the Bayern books, but especially Enna in order to really grasp what's happening in this one.