I thought this an interesting story; I think in part, because I have a number of friends with twins. This is a story of twins, and how different they are. How different their lives were. How different their thought processes were. How different their personalities are. How their love for others is the same - though their way to express it differs. How Their interests in the same subject matter is the same - but in many ways, it does differ. How their need to sacrifice for the other is the same, but how they demonstrate that sacrifice differs.
I wouldn't say this is an ideal vacation book, though if you just take one book - it is. It isn't a light read though. It isn't a quick read. It is a good read.