User blog comment:FairyRaven/Fairy Tail Chapter 435 & 436: The Cry of Victory & Memoirs, Review and Commentary/@comment-24039234-20150518203351/@comment-7418318-20150518215142

FMA isn't bad either. It's not as good as Brotherhood, but it's still good.

Also watching FMA before Brotherhood gives a bit more immersion. In Brotherhood they kind of skipped over some of the material that introduces some supporting characters and makes you care for them.

For example I doubt I would have felt much for Maes Hughes if I had only watched Brotherhood, but having him as such a long-lasting member of the cast and his constant fawning over wife and child in FMA made me care quite a bit about him.

And that sleezy guy who lorded over the mine until Ed tricked him into selling the contract, who later worked for a certain Ishvalian... In Brotherhood we only get a 2 minute introduction where FMA showed the entire incident in the mining town as an episode.

So in short, if you have the time to spare, I suggest you watch FMA followed by Brotherhood. If not, just watch Brotherhood alone.

But I strongly suggest you do watch at lesat FMA Brotherhood since it's a great series and with a nice soundtrack to boot.