I have gotten a decent amount of email from folks with various gripes and corrections and have been happy to correspond with them. I like it because this ensures that the next printing and edition can incorporate some of these things. But because you don't like a font, or don't like repeating important points, or don't know what is on the cover are not good reasons to not suggest to someone else to buy the book. Maybe the book isn't for you. A large problem (with many books) is people *think* a book is for them, but it isn't. Then they dislike the book because their ego is hurt that the book didn't seem to be written for them. But no, I don't find your gripes valid. If you find something that was wrong in the book (and not on the errata web page), broken code, points on concepts which we missed, etc... please pass them along. Those would be valid gripes. Not understanding the books layout and purpose isn't. I'd be happy to take this offline, so if you can 'slam' the book with specific and valid problems with it, you know where to find my email address. If you can't cite specific problems with it, don't go around in public arenas trashing it.
One problem with things like this (and a reason why I may seem defensive) is that it takes a lot of work to put together a book. This project took a year, and many peoples time and energy (between editing and reviewing). Then, someone comes along and says they don't suggest the book because they don't like fonts, and mentions no real problems with the book. I think that doing that is shameful. Good reviewers would say things like "Although they did X Y and Z very well, and the information was technically correct and accurate, the tone of the book wasn't useful to me." What you did was give subjective issues which pertain to noone but yourself, and precede it by saying "I wouldn't recommend it to anyone." That is a harsh thing to say, and you didn't argue your position with anything actually useful to me, or possible readers.
Anyways, just think of this next time you casually trash someones work with shallow, subjective gripes.