The lectures are interesting, informative, and well-delivered. As a light overview of Old English language and literature, with some philology and history thrown in to spice it up, the course works. That said, it tries to do too much and therefore falls short on most accounts, which is why I say that its primary benefit is as an overview to get an otherwise uninformed but curious public interested in Old English.
The material devoted to learning the Old English language is grossly deficient for that task; don't even try to use this to learn OE. This consists of 4 30-minute lectures and less than 60 pages from the guidebook. That is not to say that this content is *bad* per se. The information is accurate and well-presented. It is just that it is only enough to give someone a rough idea of the "feel" of OE morphology. If you actually want to *learn* to read OE, use material truly dedicated to that purpose.
Speaking of the guidebook, it doesn't contain course outlines like most Great Courses guidebooks do; it is just grammar instruction, and a poor one at that. Much of those pages are simply workbook templates for practicing declensions and conjugations--a waste of space that could've been used more wisely. Then follows a 24 page OE poetry reader with modern English translations. Trilling reads some of these excerpts in various lectures, but alas, there's no index telling you where to go in the lectures to hear it read. So, the guidebook is basically useless.
The fact that Trilling reads some OE excerpts in every lecture has mixed reviews on the Great Courses site. I think it is good practice. The student is acclimated to the sounds and rhythms of the original language. She immediately follows with a modern English translation. The downside of this is that it takes up time, which some people don't like. I already knew OE coming in so I was a rare listener who liked the OE reading, but then was annoyed by the translation. So it goes.
On the whole, I enjoyed the course and am glad it exists. I do wish they had made two or more courses though--one about the literature exclusively in translation (possibly separating prose and poetry) and one that was just a language instruction course along the lines of the Greek and Latin 101 courses.
The above failings I put on The Teaching Company editors and producers. Trilling is a great lecturer.