I highly recommend FMA Brotherhood and the FMA manga itself for all those interested in anime/manga. The original, older FMA anime diverting from the manga can be an interesting watch if you are not too passionate about how it follows the manga plot to a T. To me, FMA Brotherhood is more an action drama with some comedic relief sprinkled than it is a lighthearted anime. It brings the action with plots of both triumph and regret/sorrow on both "hero" and "villain" ends, nice animation for its time and generally speaking, and the anime can make you think about themes of militarization, politics, nationalism, and what it means to be part of or subjected to a nationally/regionally powerful society. If you like an action anime that provides a bit of political commentary, then this anime is definitely for you. If you want to watch a good anime regardless, I recommend FMA Brotherhood nonetheless because this anime definitely has the action, plot, and characters extremely well done. However, I don't recommend this anime if you want something consistently happy to watch, or if you want an anime where you can follow the plot SOLELY by watching the action sequences. This anime is best to follow watching both the action and the dialogues intentionally.
