It's been a little while since I listened to this series of lectures; I should have written my reactions down at the time. I will say that I recall liking the opinionatedness of the presenter. The series wasn't simply a history of epistemological theories (presented in an "objective" manner), but rather Shieber has his pet theory and the entire historical overview is there to present and knock down past theories as a means of leading up to his theory of social externalism.
Even when I don't agree with someone, I find extensive arguments to be interesting and I thought he did a good job at pulling me along through the course. That said, sometimes his defeaters of past theories, left me scratching my head. I imagine that proponents of the views he so easily rejects could respond sufficiently, or at least suggest that despite some issues, there are important truths in their theory.
Now, if past theories of knowledge are so easily put down, then what of the social externalist understanding of testimony that Shieber supports? I would have hoped that social externalism would come across as a brick house built on a firm foundation, especially after his claiming every other theory is made of cards and knocking them down; sadly, his final solution seemed to me very anticlimactic and a let down. Social Externalism seemed to me like most of the other views he presented, containing truths but by no means a complete or sufficient theory of knowledge.
The main issue I had with his view, is that in support of Social Externalism, Shieber almost sounded like he is against individual critical thinking (suggesting it is worthless), but is rather in favor of the virtues of groupthink; one just has to be lucky enough to belong to a social network that has true knowledge; if one is part of such a group, one's job is just to simply believe what science and the mainstream media says and not to question, and to be confident one, therefore, has knowledge.
I suppose I am inclined to an eclectic approach. It would be a good exercise for me to consider the good elements I find in the different theories of knowledge