This is a great series that has remained at the top of the charts due to their amazing story that has managed to perfectly balance action, comedy, a meaningful well-plot story, and character development.
If you are wondering if you should watch FMA or FMAB, or both, well, the truth is that they are different stories. They use the same characters and they have the same personalities, but the events, the antagonist and the main focus differs for each story, the way alchemy works is also different, as well as some character's roles.
FMA is better at the first part, which FMAB, condenses too much, in less than 10 episodes, so you don't get the same emotional immersion. FMA ending is ok, FMAB ending it's outstanding, but in my opinion, both stories are worth watching. FMAB closely follows the manga.
Both stories have themes of war, crime, scientific progress, the real value of life and taking responsibility for your actions. These series are a must watch and I think everyone will enjoy them.
If you want to see a more in-depth comparison between the manga and both anime adaptations you can watch this video, just know that it contains spoilers.
The dub is great for both series.
HOW TO WATCH:
Since both stories diverge greatly, you have 2 options to watch them:
1. Watch each series in full from beginning to end.
In this case, watch FMA (2003) first for the best experience. They were released this way and FMA 2003 won't spoil anything from FMAB, while FMAB condenses the content too much, spoiling parts of the story that were done way better in FMA, for example, if you really want to find our why Shou Tucker is the most hated character since FMA release in 2003, then it's best to watch FMA (2003) first, this is one of the most notable events within the series that shapes the lives of the main characters and is way better in FMA, while in FMAB it goes down in one episode spoiling the surprise if you decide to watch FMA later, so I strongly recommend you watch in release order for this reason. In this case, the order will be:
This is my favorite way of watching the series as it's the full manga story encompassing the best parts of both shows. Note that watching this way won't spoil anything if you decide to watch each series in full later. However, note that you will notice slight differences in some character's personalities. In this case, the order will be:
Differences with Brotherhood (Contains Spoilers)
Regarding as Why to Watch FMA, this is an extract from sothis review:
"Full Metal Alchemist is, in a word, brilliant. It's hard to explain exactly why it was so good, so you'd probably just have to see it for yourself. There is a perfect blend of comedy, action, intrigue and excitement all in one. Filler episodes are wonderful and fly by quicker than a bullet train. I never at any point in the series was bored, even for a second. In the beginning, there are a great deal of mini-arcs that deal with events in a certain town or location, but all are still somewhat involved with the main plot. Once the end of the series rolls around, you realize that all of these seemingly unconnected events or places really ARE connected, or come back into play somehow. This comes down to FMA's epic nature at heart, and maybe that's why it was so good, who knows.
FMA is an extremely dark series, with plenty of very messed up scenes and ideas. "Wow" came to mind many a time when something gruesome happened yet again, and this continues throughout the entire series. There are plenty of twists and turns along the way (with one really major one near the end), most of which will surprise you and catch you off guard. There is also a plethora of character development and characters in general, all of whom have a rich background and history. The empathy we feel when a character is killed, for example (or hurt in any way) is present throughout the entire series because of how well the character interactions were presented in tandem with the plot. Truly, there aren't enough good things I can say about the story... it reels you in in the first few episodes and holds on tight till the final act (which is a very beautiful yet open ending, setting itself up nicely for the movie). There are barely any series I see that make me want to watch the next episode so badly, and this is one of them, for 51 episodes in a row. A 10? Can't give it anything less.
I can't say enough good things about this series, but I feel like watching it for yourself would make you understand why I gave it a perfect score. Everything about the series is flawless, from the epic and involved story to the pacing and mood, to the music and animation and depth of characters. It really is rare for a series like this to come along that not only succeeds at keeping your attention for 26 episodes, but for 51. What are you waiting for? Check this out as soon as you can." -sothis
Watch. This is the Sequel & Ending to the FMA 2003 Story Line.
If you are coming from FMA (2003) Episode 25, then watch in this order:
Although this series is advertised as a remake of FMA (2003), in truth, only Episodes 2-10 are the remake of FMA 1-25 (Episodes 26-27 are similar but the original story starts to emerge in FMA), after that, FMA starts to diverge greatly to the point that it's a completely different story, different focus, and different antagonists, therefore FMAB after episode 11 is all new material from the manga story.
Optional side story, not in the main timeline, but its an ok watch. It's best to leave at the end of the Brotherhood series and consider it independent of the main story, since it takes what we knew about the way philosopher's stones worked, and rewrites it, rather than adding to it. Is for this reason some people don't like the movie at all.
The dub is good.
Skip, they are just pathetic comic relief with awful animation.
Skip, this is just a Recap.
Skip, these are just boring explanations of some concepts of their world and short stories that are mostly comedic relief or slice-of-life.
Skip, this is just silly comic relief.