Saying I have a love-hate relationship with John Piper would be too strong a statement. It's more a love-meh relationship. I love his preaching- heck, I'd be willing to say that in my opinion he's easily the best living preacher. But I've regularly found his books to be, well, meh. Not that they're theologically bad, it's just that they're long and dry and only really work if you read them in his voice in your head, and that gets tiring after a while. So I picked up The Pleasures of God (provided free by the publisher on the condition that I write a review- not necessarily a good one) with no more than moderate expectations. The book lived up to my expectations.
Summary: The Pleasures of God is about just that: what makes God happy? To that end, Piper broke the book into two sections: 1) The pleasure of God in Himself (in Jesus, in His actions, in creation, in His own Glory); 2) the pleasure of God in His people (in election, in justification, in providence, in our prayer, in our obedience).
Analysis: Like pretty much every Piper book I've ever read, it's theologically correct, full of wonderful insights, dry, and about a hundred pages longer than it really needs to be. Also, it is about how God is most glorified in us when we are most satisfied in him.
Who Should Read This Book: People who will likely never pick up Jonathan Edwards. Really, The Pleasures of God is an interpretation of Edwards' theology in The End for which God Created the World. Which is a dense and difficult book that most people will never even start, let alone finish. Even though this book is longer, it's a much easier read and the place to begin if you want to get the gist of Edwards' ideas.
Who Should Not Read This Book: People who've read more than three of Piper's other books, or who've never had any encounter with Piper before. If you've read a good number of Piper's books, you know that he just applies the same theme (God's Glory) to different topics. Which isn't a bad thing, of course. It just means that after a while it gets repetitive. On the other hand, if you've never encountered Piper, his books just aren't the place to start. I recommend getting on his website (www.desiringgod.org) and listening to a few of his sermons. If you enjoy them, pick up the book and give it a read.
Having said all of that, the idea behind the book is a critical one for modern Christianity. Especially in modern America, where our idea of God bounces between a kindly, inept grandfather figure and a buddy who mildly approves of everything we do, Piper's revelation of the Biblical theme that God is ultimately delighted in Himself, rather than in us. So I suppose technically another category of people Who Should Read This Book is that of those modern Americans who've bought into the various lies about God that modern American culture shills to us 24/7...
Overall, this is a worthwhile read, and very useful as a devotional. I recommend reading it with a group and taking advantage of the study guide in the back.