I found Iron Queen an entertaining read. Its definitely a YA book, and keeps pretty shallow with the characters, but I'm really interested in Kagawa's system of magic and the interactions between the 3 elements. The romance part of the book was annoying, but didn't dominate the plot to the point where it was overbearing, which frequently happens in this type of book. (*ahem* Mind Games) 
 I'm worried for the content of the fourth book, mainly because it was supposed to be a trilogy that was abruptly changed last minute. It would be really hard to stick on a fourth book after writing 2 with the intention of ending on 3. However this doesn't really relate to Iron Queen, so I'm not entirely sure why I'm ranting about it. Anyways...