It is clearly sourdough bread, though the characteristic flavor is more subtle in mine than I'm used to. If memory serves, however, this is partially related to the starter's age, so clearly a 1-day-old starter and a 100-day starter are going to produce different breads.
Beyond that, it is hard to tell how many of the characteristics of the bread come from the technique she describes for making it and how many come from the fact that it's a naturally leavened bread. For instance, I don't get a whole lot of oven rise (the final rise which happens as the dough cooks), which might be because the natural yeast are not as strong as commercial yeast (which are designed for high-rise doughs), or might be because I'm not kneading it enough (which produces nets of gluten that expand as the yeast pump out their CO2).
So the question comes down to: is it worth it? Maintaining the starter is a lot of work, with a lot of waste, but this can be alleviated by keeping less starter active and by keeping the starter in the refrigerator until a couple days before you're ready to use it (at which point it needs to be fed on its regular schedule until baking day). These are both tactics I will probably use soon, but in the interim I'm making different breads from the book to see how they are.
And this brings up another point about this whole process. Once you've got your starter made according to Silverton's instructions, you're sort of stuck with her recipes. Delicious as they are, they don't give you a lot of guidance for adapting recipes with commercial yeast to ones with the starter. For instance, last night I made pizza dough, but I had to use commercial yeast because I couldn't find a recipe for pizza dough in her book, and I don't know what I should do differently. Maybe it's in some sidebar somewhere, but I haven't found it yet.