I'm actually a few chapters into this book and am really liking it so far, especially the light style!
When the version I have (v1) was written, Xcode 4 was the standard, and now Xcode 5 is out, but that hasn't been a problem. The weirdest thing is that the debugger is different, so some of the output doesn't match the examples in the book, but they explained that in the beginning:
Looks like v2 of the book is out and updated for Xcode 5?
I bought this book the iBooks Store and it's been pretty nice having iBooks open on my laptop screen, and then having Xcode open on an external monitor.