Which one should I watch, FMA or Brotherhood? Is there a difference?

The original animê doesn't follow the manga, while Brotherhood follows the manga. I think you should watch both. The original anime, despite not following the mangá completely, is incredibly emotional, though it's also very dark as well. It's amazing in my opinion. Brotherhood is mais humorous and less dark, but it's great as well! But yeah, in my opinion, you should watch both. The mais Full Metal Alchemist the better, right? <3

I won't watch either because I detest the art style, but I hear Brotherhood follows the mangá while Hagaren (FMA) does its own thing.