There are other good reviews here on the content, so I won't focus on that.
I bought the Kindle version of this book to try it out for one thing, and it was easier than finding a book store!
First off, I commend Lonely Planet for releasing this in an eBook format. After travelling for eight months, it became quite difficult to find guide books, find *genuine* guidebooks, and not to mention, lug them around. At first, I thought Lonely Planet only released PDF versions, which are next to useless on an electronic device. This eBook is immeasurably better than a PDF, and is easy to read. But even with Kindle's highlighting and book-marking features, it is a bit cumbersome to navigate back and forth like you would in a regular guidebook.
Scenario: you are following the walking tour map with your Kindle, turning it this way and that. You look like a bit of a weirdo for one thing :) But then, what is sight 5? So click back-back-back to read up on point 5. Then you need to page forward-forward-forward back to the map. Hit the five-way controller to get back to the map, click to enlarge, then back to the map, rotate device. Also, walking around with Kindle in hand, I was a bit worried about knocking or dropping it.
I think once eReaders have touch-screens, guidebooks will be a bit more realistic. Until then, stick to the physical guide book is my advice.