Firstly, a couple of notes on comparing the different editions (print and online) available:
- The review of the printed book on amazon.com, criticised the quality of the black and white photos.
- The sample PDF on the informit website has very poor quality black and white photos as well. Zooming in shows that they have been compressed badly and are barely readable with poor contrast
- The pictures in the Kindle edition are in colour, and high resolution, high quality colour at that
- The Kindle Edition unhelpfully does not have a very good Table of Contents embedded - just a summary showing the three parts of the book. This is a great pity, as the book structure is complex and has many chapters and sub-chapters, which are difficult to navigate through without a detailed TOC
- I am using the PC version of Kindle for this review. I do not own a Kindle myself, but as the book description says, you need a device with a large screen (iPad, PC) to get the most out of this. The illustrations are in colour, so I would advise a colour device too (alas, no Kindle Fire in the UK yet!)

So, what about the book content itself?

I found it quite easy to read (once I had found the relevant section), and the level of the text was easy to understand (I am an ex-VB6 programmer and all the examples are in VB.Net rather than C#, so this suited me). I found that the example code illustrated the points well, and there are enough screenshots to illustrate the points in what is a very GUI-oriented tool.

The book itself has a lot of information on the more detailed technical aspects of LightSwitch. In some cases, you are referred to other articles, including some written by the author himself. The book itself is over 800 pages long (15,000 locations in my Kindle!) so it is pretty encyclopaedic anyway.

The final minor niggle is that the grammar and writing style throughout the book isn't perfect.
I would guess the author is not a native English-speaker (Italian is his native language, I believe), and that the editors did not manage to correct all the stylistic deficiencies - hence we get some interesting phrases such as "about LightSwitch, applications will be managed as Web roles", rather than "in the case of LightSwitch, applications will be managed as Web roles". Future editions should aim to correct this, as it does somewhat compromise readability.

So, in summary:

Pros
+ Readable on Kindle for PC
+ Comprehensive coverage
+ Good technical depth

Cons
- Less readable in print (according to the amazon.com review)
- Kindle version Table of Contents could do with breaking out the chapters and sub-chapters
- Grammatical errors / English writing style can make some sentences difficult to comprehend