What's your take on 'After The Prophet'?

Has anyone read this by Leslie Hazelton?

Someone recommended this to me to better understand the Shia/Sunni split saying that since this is written by a non Muslim author, it is an unbiased account. What's your thoughts on it if you have read this? Is it authentic?Biased?

So far I like her way of narration (like a story) but it wouldn't be a lie if I say I was shocked and a little disheartened by our history.

Edit: Thankyou everyone for your thoughts. I was at 70% and read some negative reviews about it that's why I asked for you guys' prestigious opinion. Will continue to read it.