I've never seen it. From what I've seen in fanfic, fanart, and people fanning over it, the characterization seems alot like One Piece. Natsu's character instantly reminded me of Luffy. Happy to Chopper, Juvia to Sanji, etcetera. I've also heard the amount of episodes is ungodly, which means the anime was a huge hit at one point or another, ultimately creating haters that hate on similar anime (like One Piece, Naruto, and Pokemon) just because it's mainstream and they don't have the time or want to get into such a long anime.