I refuse to answer because I might incriminate myself. Since I am trying to profess that I am blues/rocker guy, any text I place would ruin my good reputation.
For the sake of argument, without admitting anything, hypothetically, I would surmise that their music was well timed for that generation. Their music was well received and their skills were more than mediocre. They wrote their own songs and the best reason for liking their music was that they actually played their music!
Based on the preceding paragraph, it is of the opinion of the writer that Spandau was the better band because of better song writing. If the rivalry was based on music videos, because of the video interpretation of the aural song "Girls on Film", Duran Duran had better "vision".