To be honest

It really grates when people have to qualify what they say with 'to be honest...'
I reckon you should just be honest, right?

I wrote a review of a book (Selling: Powerful New Strategies for Sales Success) that I bought (on Amazon) recently. It was written by Kevin Hogan et al - someone whom I follow closely on the net, and whom I admire for subject knowledge as well as marketing savvy.

I gave it 2 stars. Seventeen other reviewers averaged 5 stars.

Should I have been brutally honest? (See previous post.)
Is that really what is wanted in 'comments' sections?
Is that the right forum?
If I can't write a better book, do I have the right to criticise?
How many of the 5-star comments are seeded by friends and fans and how many are genuine?

Having said all of that, I thought the book did offer a few nuggets that are worth the $20 -odd bucks spent on it. But then again, I think any book on the planet represents great value, because one sentence could change your life.