I personally think that the English dub doesn't hold a candle to the original version. I think that the voices in the Japanese version suit the characters much better and that the Актёрское искусство in general is better, and I'm iffy about the dub's translation, too. I don't have anything against dubs или FUNimation but I really think that they could have done a better job.
Never ask this question. Both are perfectly valid. The problem is that Japanese is a language we don't understand but we like, so what the mind does is fill the gaps in our understanding with positive feelings which can lead to people thinking that it is the only way to enjoy a show. I have no doubt that the Japanese version is good, however as somebody who does not speak Japanese my opinion on it's quality does not account for anything. I haven't seen the english dub in great detail but it seems fine.
Honestly, I don't mean to offend, but I enjoyed the Japanese voices much еще than I did the English voices. FUNimaton did a decent job, but, as I was already used to Japanese, the voices sounded off and the translations were a little iffy. I'm not one to hate on dubs, and honestly some dubs (like FMA and FMA Brotherhood) are actually quite well done, but in this case I think that the original actors and Актрисы did better.
Ohoh. Japanese sub. The English voices sound constipated and unnatural, especially Eren's. I mean the casting was okay, it's just that the way the actors speak in the dub, they just sound weird. I dunno. Like if a slowly inflating balloon could talk, that's how most of the characters in the dub sound like.
But to each their own, dub IS easier to watch for most. /shrug