Tenchi in Tokyo is yet another spinoff of the Tenchiverse, and often maligned as one of the worst entries into the franchise. As it was not written by Masaki Kajishima, it is not considered canon to the main continuity, however it is apparently canon to Tenchi Universe. It is generally derided by fans for taking attention away from the main characters and altering the overall feel of the work.
Standing in the Battledome
As for power, it is actually rather impressive, though not nearly as much so as the Kajishima canon. The main villain is a universal threat, for one.