My kids really enjoy them, and often choose them over things that are not really educational at all…but they also choose Story of the World cd’s, so maybe they are just strange. Or I have successfully endoctrinated them to love history :).
They move really fast, so it helps if the kids are in the 8-12 year old range, IMO. We do get several viewings out them before they ‘get’ everything that the host is saying.
I would say that if your kids like them, they are good for reinforcement. Maybe you could check them out or watch a sample first to see if they understand and get the humor?