When I first started Altered I had to keep myself from comparing it to Brigid Kemmerer's Elemental series - 4 boys, special abilities - but this book was very distinguishable from it and really held its own! 
 One of the most noticeable aspects, and one I was impressed with, was Jennifer Rush's ability to give each boy their own distinct personality. Sam was the serious leader, Trev was smart and thoughtful, Nick was reserved, and Cas (my favourite of the four) was a fun and lovable goofball. I loved how they interacted with each other and the dynamics of their relationships. 
 I'm still not quite sure how I feel about Anna. There's no doubt that she's a strong, logical character, who thankfully can hold her own in tough situations, but I didn't really have a solid connection with her. Her relationship with Sam annoyed me sometimes just because it tended to run hot and cold, but I suppose that comes with the territory when he was locked up in her basement for several years. 
 The plot was fast-paced and exciting as the story followed along the lines of scavenger hunt. It gets the adrenaline going because you're never quite sure when, or if, the Branch was going to catch up with them. With the addition of memory loss, there was also an unreliability issue with the characters, which certainly makes things more interesting. 
 With lots of action, and some romance and plot twists mixed in, Altered makes for a fun read and a solid debut overall! 
 Also, can I just say how much I love this cover?!