I'm an instrument-rated private pilot. Although Flight Simulator isn't a perfect substitute for real-world flying, it does have its pros (not least of which is that it doesn't cost $139/hr to rent 'wet.')
I've had this book since October, and I love it. (I would have loved it even more if I'd had it several years ago when I was earning my license and ratings. It's THAT helpful.)
What I'd add to the other reviews is that the two authors -- both flight instructors -- do an excellent job of pointing out where Flight Simulator-flying and real-world flying differ, as, for instance, in ATC communication, available IFR clearances, and the operation of the G1000.