Since I've started recording the full broadcasts a full year ago, there have only been two I've saved to disc (I usually just burn copies of the nightly digests and delete the full broadcast recording later) -- the one when Taiho was guest/color commentator, and yesterday's with Demon. Even though I was at the Kokugikan yesterday, I still watched the full broadcast last night just to hear this guy -- as has been said he really knows his sumo, and is funny to boot (I loved when he "corrected" the hanamichi reporter and said you shouldn't call the woman Kitazakura slammed into a "obasan" (old woman, grandmother) but rather a "fujin" (woman)). And as was noted, he really made those post-bout interviews sing. As Takanonami rightly admitted, there really was no need for him (Takanonami) to be there (although all three of them, NHK guy included, were great).
Here is Demon sitting at the "mukoujomen" location during Makushita bouts yesterday: