I feel that Otherworld has managed to make a really good backstory for these two young adults, a really interesting and sweet and complicated history. This makes me want to read more about them, and follow their story. I feel I got a great view of their worlds - two very different and interesting ones.
The world building is good; Otherworld feels like an awesome place to be - you can be anything you want to be (well, as long as it's somewhat human) and do exactly what you want to do. It's world is vast and exciting. The different types of NPC's they meet in this world is interesting too.
The real world is seen from a really rich kid, but he's got a good head on his shoulders. He's smart and nice, and doesn't really care about money. He cares about his childhood friend, the only love he has in his life (his parents being rich and absent). I care about what happens to him, and want him to get his friend back.
I really enjoyed this book, it's not a new favorite or even a 5-stars, but it's a really enjoyable and entertaining read. I'm looking forward to the sequel.