With the Kane Cronicles, Riordan ventures into a new world, so to speak. I loved the Percy Jackson books and The Heroes of Olympus are more than promising, but the Kane Cronicles just doesn't click to the same tune. Riordan switches from Greek mythology to Egypt mythology, and it would have worked if it wasn't for the poor character personalities of the two protagonists. Many people do not recall learning about the Egyptian gods like they do with the Greek gods,and thus there is a set back already. Add to this confusion with two under-developed characters and you have quite a mess.
It took me over half the book to actually get into it and familiar with the characters and gods. The second half was much more action oriented and you begin to understand the gods and where they came from. The characters are very childish. Sadie being 12 and Carter being 14, you want them to be like 11 year old Percy, but they argue like the really are children and it is annoying. Sadie has an attitude that you wish would go away and tell her to grow up, and Carter is very insecure about himself and his talents. Each character gets 2 chapters to talk at a time, and sometimes you wish it would just remain as one character telling the story. When reading the entire book, you can easily get bored of the monotomous feuding and it takes away from the story altogether.
As I mentioned earlier, this series treads new ground with the less known which is Egyptian mythology. The gods are new and not very awe-inspiring, while the whole 'House of Life's' magicians just don't seem real. It's hard to picture these so-called magi running around, drawing protective circles around themselves and then throwing down their staffs to turn it into some kind of animal to protect them. That mixed with the magic portals of egyptian architecture and you start to feel a bit of nonsense is going on here.
I have read this and Throne of Fire with an open mind, but a lot of times I get frustrated with Sadie being so immature that I just want to quit reading and find another book. So I tell you, borrow this book from a Library and give it a shot. If you love it, you should definitely buy it. But if it doesn't do anything for you, then don't feel bad about returning it to the library now that you've read it for free. Enjoy.