Well, Sailor Moon has had all 5 seasons redubbed, something far more accurate than the original, and the original never got to season 5.
Fan subs can sometimes be absolute garbage, ala Mitsume ga Tooru, which had some of the worst English subs I've ever laid eyes on, though it was English subbed by Russians. Same with Spirit Hero Wataru, the movies are subbed fine, the anime, oy vey. You'll want to tear hair out by how bad it too is subbed.