I don't recall Sailor Moon ever approaching the popularity of DBZ (in the United States at least). It seemed like every kid in America was glued to the TV in the 90s watching DBZ on Toonami. Pokemon was probably more popular than DBZ, but much of that was due to the influence of the Pokemon Game Boy games, and obviously the trading card game.

I think DBZ was the first massively popular anime in the western world that leaned heavily into the shonen tropes. Pokemon appealed more to a younger audience, and Sailor Moon was more of a shojo anime.