This is a great biography of Kennedy. Yes, it's very glowing, but Sorensen clearly looked up to JFK (as many did), and this was originally written very soon after his death. The book is very detailed, and very dense. It's not a quick read, but it is certainly fascinating and the detail sometimes very revealing.
An intimate portrait of JFK, anyone interesting in learning more about him will find this book very informative and well-written. The only reason I give it 3.5 stars, instead of more is because it is a rather slow read. Robert Dallek has written perhaps the best biography of Kennedy, benefiting from historical and personal distance from the subject, which is why I'd recommend that first.