Defense matters. Offense matters more. We've seen that the last few years. Jags, Bears, Patriots, and several more all had fantastic defenses but bad offenses. They all lost. Yet the teams with top offenses and mediocre defenses are consistently among the last teams left.
49ers have a stout defense. But they also have one of the most efficient offenses. Balance>offense>defense
i'd say balance>defense>offense. if i can only have one, i'd rather have defense.