I've learned C++ from this book first, a few years ago, so my experience is the that of a novice.
On the writing style, I agree with those who say that it could have been written in a clearer way. The reading sometime had to proceed slowly, and sometime turn back a few pages and restart.
On the content, instead, I think that no other book brings the same knowledge in both quantity and quality.
It comes as no surprise that being Stroustrup the first inventor of C++, few people knows it better than him. Through this thousand of pages it is possible to learn plenty and plenty of details about the language. But should is stop here, it would be just another Kernigan & Ritchie. Indeed, the book brings much more. The language is explained through the use of a lot of examples that in reality are true insights on programming techniques. Perhaps you'll follow the classic path of buying this or some other big reference on C++, and then some other lighter book on tecniques and/or coding strategies. I did it, passing through exceptional books (Coplien, Koeing, Meyers). Now, looking back, I realize that much of the stuff I've learned through these latter books, could have been learned through Stroustrup's as well. All this stuff is there. The problem is that you learn them together with the language and the OO notions, so if you are a novice they could not receive the deserved attention (and perhaps they don't have the deserved space in the book. But, after all, I find they are "add-in"s, not the main subject).
And there's still something more. Through the chapter Stroustrup exposes his view on the OO subject. It's a personal view (that lead to the language development as a support), but it's a good one, on my opinion. One that, among the many, deserves respect and that can get a direct match on the most widely used language, together with C.