When I was at Oxford, England for a few months, I took a String theory class (not even Super STrings). From day one, it was about soliving imaginary integrals and hardcore math. There really wasn't any "physics" that I could ascertain. Now mind you, I never was a stellar physicist and this is a hardcore class, but I was still impressed by the fact that the class started with math and that it was up to us to "deceipher" the physics behind it.

We did not use Greene's book but another textbook and this was 8 years ago. Perhaps things have gotten better, perhaps the textbooks have gotten better, I don't know. But I do know that Strings are our best hope for GUT and yet ironically the worst hope for experimentation.