When you use subtitles a lot like I do, like for everything including english shows and even dubbed anime, you get used to reading the subs. Also, netflix has the english dub available. Just go to the caption window thing and select english audio.
As far as sub/dub goes, dubbed anime can veer off from the original subbed version, like you see with one piece's dub by 4kids. or sometimes the dub voice actors are just plain bad. Some also don't make a new animation for the new dub (as japanese and english are very different languages) which looks sloppy and bad.
But generally who the frak cares it's the same frakking thing just one is written and one is frakking spoken for fraks sake. For someone who doesn't know japanese it's essentially the same thing. But I can give you assurance that the FMA dub is very, very good. For both series.