I'll definitely be leaving reviews for the books, and it will be a pleasure. Just getting my thoughts together.
FJL brings up something I've wondered about Amazon reviews. I've finally come to believe that only in the most extreme circumstances does anything ever get noticed by another user. There have been three, maybe four times, that I've come across something so unbelievably absurd that I take the trouble to click on "see my other reviews" to see what's up with this person. In every instance, I was rewarded -- there was some notable pattern or other. Or it was that person's only review on Amazon, ever, which was just as telling.
Like BK says, nobody cares. I'd go so far as to say it's expected. Leaving a string of similarly positive reviews for a series of works from one person or company doesn't even come close to behavior that merits notice. For my part, I try to say something that's unique to my own experience of the thing. And even if that isn't so easy for one reason or another, I've been assured that a simple "Loved it!", with five stars, does a world of good.