I'll start by saying that I'm a complete novice when it comes to the I Ching. I'd heard of it and knew about John Cage's use of it in his work, but had never investigated further than that. This is the first book on it I've ever read, so my perspective is that of a total novice.
I have to say, for a first-timer, this is pretty approachable. True, when I first started reading it, I got a bit bogged down in the introductory detail and gave up before trying a casting, but when I came back to it, with a specific situation to cast in mind, it all started to come together. There's a wealth of information in here, but the actual instructions on how to cast (both with coins and yarrow-stalks although I've only tried the coin method so far) are very clearly presented and really make it easy to test it out. Once you start casting, the other stuff in the front of the book starts to make sense, so I'd recommend at least skimming through the earlier part so you've got an idea of the concepts and know where to go back to once you've started to cast.
I understand that Secter's work on transitional hexagrams is a new interpretation, and I have to say it made a lot of sense to me and provided some really interesting perspectives on my questions. He also includes a section at the end on how to use the I Ching without going through the divination process, so if you're a sceptic and don't believe in any of this universe-responding-to-questions business, there's an I Ching option for you too :-) I understand that his coin-based casting method is also an innovation, as it returns the same probabilities as the yarrow-stalk method.
So if you're thinking about trying out the I Ching for the first time, I can highly recommend this book as a clear guide.