I have not taken them, but am interested in doing so just to be certified and thus a bit more marketable.
I have read mixed reviews on the courses. I believe you need to take two classes and pass with a certain score on each. You can also just take the test on the first class since it's more basic for experienced users of Silk.
Please post your experience after you took the classes. Most importantly if the course was overall worth it and if you got what you wanted to from the course.
I would take the classes in a heartbeat if my company had the funds to do so, but I am thinking in perspective of one who would pay out of pocket for the courses.