As I started reading this, I thought to myself 'read with a pinch of salt', expecting it to be rather salacious and not very credible. But by the time i got to the end, I was hooked, and was reading it intently. I found the parts about Eva Braun the most interesting, especially the last few days of her life in the Bunker. The authors bring vividly to life what life was like in Berlin in those last few days of the war - hellish for all concerned.
As for Hitler's sex/love life? I dare say a lot of the more outrageous stuff about him was rumour and lies - not because I think it was unlikely, but that it was most likely said and spread to mock and discredit him. (The one testicle thing being a prime example.)
I found the psycho sexual analysis of Hitler tedious after a while, especially when the authors tried to use it as a reason why he did what he did, politically. Not to mention the suggestions of 'if his dad was not so brutal/if so-and-so loved him' etc. These things may have influenced him and helped to shape him, but I doubt the prevention of the death of his niece/lover, for example, would have saved the world from going to war, eventually.