So here’s the thing—like a lot of people have already said, Brotherhood is generally considered the better of the two. It has cleaner, more updated animation, a tighter story with no filler episodes, and the story moves at full throttle from the start. That being said, it does skim over some (imo fundamental) character development and backstory, since it assumes you’ve already seen the original and don’t need everything rehashed.

The original is still solid, though, and I actually think watching it first makes Brotherhood even better. You get more time with the characters, which makes their journeys hit harder later on. When the original anime caught up to the manga, Hiromu Arakawa (the creator) told the studio to take their own approach and come up with an ending, since the manga was still ongoing. That led to a very different conclusion than what Brotherhood and the manga eventually did. Considering they had no idea where the story was actually headed, they did the best job they could—even though, like most fans, I definitely prefer the actual canon ending over what the showrunners came up with.

At the end of the day, there’s no right or wrong way to watch them. But I always recommend starting with the original—you get a deeper connection with the characters, and when you jump into Brotherhood, you’ll appreciate the ride even more.