There have been a lot of books written about Heidegger. This is the only one to provide you with the very experience of Heidegger. If you're a student of the great overturner of Plato and you haven't read this book, chances are you missed all the important (though esoteric) stuff. And you definitely won't get his book on Kant or On the Way to Language. The selling point for me for this relatively slim volume was that Fynsk is lucid and friendly, unlike many of Heidgger's disciples in the English-speaking world. Like Deleuze, he is interested in connecting with the reader, not brow-beating him or her. But unlike Deleuze he doesn't write in a stream of consciousness (i.e. first draft is last draft) style.
We need more books like this. I hope he writes a companion volume to the later Heidegger. We could sure use it.