Unsu is a very old kata. It is simple and short but very efficient to teach the practical principles of Naha kempo. Personally, I think it's much better to teach it to students after Sanchin because it gives them a real fighting skill. I think it's much better than the Gekisai, who to me are just kihon.
The version below was transmitted by Choyu Motobu (the "master in the shadows" of Miyagi) and still taught today in the old Goju / Naha-te schools. André Mucci, 5th dan, performs the kata.