Depends where the original thing started. A Manga adaptation of Anime rarely feels good (Gurren Lagann) and Anime adaptations sometimes take unnecessary liberties with the story or leave out important elements, in my personal experience.
Sometimes it turns out all right though, the first FMA Anime's latter part broke away from the original story but was still pretty good.
Sometimes it turns out all right though, the first FMA Anime's latter part broke away from the original story but was still pretty good.